U.S. patent number 3,881,310 [Application Number 05/379,563] was granted by the patent office on 1975-05-06 for clock adapted to be synchronized by alternating current in a wireless manner.
This patent grant is currently assigned to Diehl. Invention is credited to Erich Gerum, Alfred Meisner.
United States Patent |
3,881,310 |
Gerum , et al. |
May 6, 1975 |
Clock adapted to be synchronized by alternating current in a
wireless manner
Abstract
An electric clock having an electromagnetically operated
mechanical oscillator with actuating coil means and a magnet on the
mechanical oscillator cooperating with said coil means. The natural
frequency of the electromagnetical oscillator is double the rated
frequency of an alternating current network. A transmitter
connected to the network transmits a carrier wave at a supersonic
frequency which is modulated by the network at double the network
frequency. A receiver at the clock receives and demodulates the
carrier wave and supplies the pulses to the coil of the mechanical
oscillator. An electrical oscillating circuit at the clock is
connected to the coil of the mechanical oscillator and a control
arrangement disables the electric oscillator when the pulses
derived from the carrier wave coincide in frequency with the
natural frequency of the mechanical oscillator by enabling the
electric oscillator when the network frequency departs a
predetermined amount from the natural frequency of the mechanical
oscillator.
Inventors: |
Gerum; Erich (Nuremberg,
DT), Meisner; Alfred (Nuremberg, DT) |
Assignee: |
Diehl (Nuremberg,
DT)
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Family
ID: |
27431214 |
Appl.
No.: |
05/379,563 |
Filed: |
July 16, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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230326 |
Feb 29, 1972 |
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Foreign Application Priority Data
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Mar 2, 1971 [DT] |
|
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2109707 |
Mar 2, 1971 [DT] |
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2109705 |
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Current U.S.
Class: |
368/47; 968/510;
368/52; 968/490 |
Current CPC
Class: |
G04R
40/02 (20130101); G04C 11/02 (20130101); G04C
3/14 (20130101) |
Current International
Class: |
G04C
11/00 (20060101); G04C 3/00 (20060101); G04C
11/02 (20060101); G04C 3/14 (20060101); G04b
001/00 () |
Field of
Search: |
;58/35W,33,24R,23R,23A,23BA,23AC ;318/16 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wilkinson; Richard B.
Assistant Examiner: Weldon; J.
Attorney, Agent or Firm: Becker; Walter
Parent Case Text
This is a continuation-in-part application of co-pending Ser. No.
230,326 -- Gerum et al. filed Feb. 29, 1972 and belonging to the
assigne of the present invention.
Claims
What is claimed is:
1. In combination with an electric clock and a transmitter, said
clock having therein an electromagnetically operated mechanical
oscillator with a predetermined natural frequency which is a
selected whole number times the rated frequency of an alternating
current network, said electromagnetically operated mechanical
oscillator including actuating coil means therein, said transmitter
that generates a carrier wave being installed at a location remote
from the electric clock wherein said mechanical oscillator is
provided, aerial means respectively being provided for effective
relationship between said transmitter and said clock, modulating
means in the transmitter, said transmitter being adapted to be
connected to said network and including means operable to transmit
said carrier wave at a higher frequency greater than that of
audible sound and modulated by said modulating means effective with
said network at a lower frequency which is said selected whole
number times the frequency of the network, a receiver at the clock
having an input end and an output end, a demodulating means in the
receiver, said receiver being adapted to receive said modulated
carrier wave at said input end and including amplifier means
operable to amplify and connected serially with said demodulating
means to demodulate the wave to develop first pulses at said lower
frequency at said output end, means connecting said output end of
said receiver to said coil means to supply said first pulses
thereto, a battery powered electric oscillator at said clock
developing second pulses at said natural frequency of said
mechanical oscillator and connected to said coil means,
semi-conductor control means in circuit between said electric
oscillator and said coil means normally disabling said electric
oscillator, means lying between said coil means and said electric
oscillator sensitive to the supply of an impulse signal in response
to deviation of frequency of the network by a predetermined amount
from the rated frequency thereof to enable said electric oscillator
to operate, and comparing means comparing the frequency of said
first pulses to the said natural frequency of said mechanical
oscillator connected therewith and connected to supply a said
impulse signal to said semi-conductor control means in response to
deviation of said network frequency by a predetermined amount from
the said rated frequency thereof, said receiver at the output end
including a first transistor having the emitter-collector path in
series with said actuating coil means and the base connected to
receive said first pulses; said electric oscillator comprising a
second transistor having the emitter-collector path in series with
a portion of said actuating coil means and said battery; said
semi-conductor control means comprising a third transistor having
the remainder of said actuating coil means connected between the
base and the emitter thereof, the collector of said third
transistor being connected to the base of said second transistor
and via a capacitor to the emitter of said third transistor and via
a resistor to one side of said battery, said mechanical oscillator
having magnet means linking said remainder of said actuating coil
means to develop pulses therein during oscillation of the
mechanical oscillator.
2. A clock in combination according to claim 1 in which said
transmitter comprises full wave rectifier means connected to the
network and supplying modulating pulses to said carrier wave of
said transmitter at double the frequency of said network.
3. A clock in combination according to claim 1 in which the
frequency of said carrier wave is within the range of from about 20
kilocycles per second up to about 50 kilocycles per second.
4. A clock in combination according to claim 1 in which said
receiver comprises a filter means including RC elements connected
between said amplifier means and said demodulating means.
5. A clock in combination according to claim 4 in which the RC
elements in said filter means are so dimensioned as to obtain
maximum damping at carrier wave frequency.
6. A clock in combination according to claim 1 in which said
transmitter and receiver comprise aerials for the respective
transmission and receiving of the modulated carrier wave.
7. A clock in combination according to claim 6 in which said
aerials are arranged vertically.
8. A clock in combination according to claim 2 in which said
transmitter includes current controlling means in circuit with
output location of said rectifier means.
9. A clock in combination according to claim 8 in which said
current controlling means is in series with outlet location of said
rectifier means.
10. A clock in combination according to claim 8 in which said
current controlling means is in the form of a glow lamp having an
ignition voltage which is about half of the normal network
voltage.
11. A clock in combination according to claim 8 in which said
current controlling means is in the form of Zener diodes arranged
in branches of the rectifier means.
12. A clock in combination according to claim 1, in which said
means sensitive to the supply of the impulse signal thereto to
enable operation of said electric oscillator and said comparing
means comprise a loosely-coupled pulse comaring circuit receiving
pulse sequence to be compared with network frequency, and
electrical mechanical pulse generator having a mechanical resonator
means in resonance with the synchronizing pulses, the signals in
said receiver after amplification and demodulation being conveyed
to said pulse comparing circuit, during resonance condition there
being energy supplied for maintaining oscillation thereof and for
synchronous drive of a driving mechanism for an indicator from an
amplified input signal of said receiver, and an electro-mechanical
pulse generator means which disengages itself from the
synchronizing pulses and which alone takes over the timewise proper
control of the driving mechanism when the network frequency
deviates from the rated frequency by at least partial fractional
amount up to and including complete failure of network frequency.
Description
The present invention relates to a clock which is adapted to be
synchronized by low frequency network current, the driving
mechanism of which is actuated by a battery built into the clock,
and if desired, through an amplified circuit.
Clocks have become known in which a synchronous motor is employed
for driving the indicating mechanism, which motor is driven in
synchronism to the network frequency while being directly connected
to the alternating current network.
Also, clocks have become known which are in direct conductive
connection with a master clock, which latter gives off
synchronizing pulses for keeping the other clocks in synchronism.
The present invention, however, does not relate to clocks of the
above mentioned type which require an electric line connection for
supplying the current or for controlling the clocks. It is rather
an object of the invention to provide synchronizable clocks which
are independent of a master clock and which do not require a line
connection so that they are no longer bound to a specific
location.
Also, clocks have become known which are synchronizable in a
wireless manner and which are synchronized by a radio transmitter
which as time standards emits pulse-shaped signals, for instance,
in sequences of seconds. In the receiver, the time giving pulse
sequence received from the emitter is in a comparator containing
two NAND gate circuits compared with a second pulse sequence which
is furnished by an oscillator of the clock. When the deviation
between the two pulse sequences to be compared with each other
exceeds a previously fixed value, the comparator furnishes signals
to a correcting device which so influences the pulsing sequence
generated in the clock that the error in the deviation is again
compensated for. To this end, additional logical circuits with AND
and OR gate circuits and a control circuit are employed which
prevents a correction of the pulse sequence generated in the
receiver, when transmitting disturbances have occurred between the
transmitter and the receiver. However, not only are such radio
transmitters and the master clocks employed for generating the time
standard of rather complicated construction and therefore liable to
disorders and expensive, but also with the other clocks which are
to be synchronized by the radio signal, relatively considerable
technical equipment is necessary in order to neutralize or
eliminate possible atmospheric disturbances. In addition thereto,
it may also be mentioned that from case to case in conformity with
the geographic location of the receiver, the signals coming from
the radio transmitter can be received only poorly. When, for
reasons of cost, such additional technical equipment is not
admissible and when the synchronizable clocks are to be employed in
public offices, factories, private offices and dwellings, other
means have been resorted to. More specifically, the fact that the
frequency of the customary alternating current network, at least
when considered over a longer period of time, has a high constancy
has been taken advantage of for synchronizing clocks. To this end,
the low frequency electric or magnetic alternating fields which
forms in the form of a stray field in the vicinity of conductors
connected to the network have been received by means of an aerial,
and the signal after having been amplified has been used directly
for driving or synchronizing the driving mechanism of the clock,
which driving mechanism is actuated by a power source built into
the clock. Although these clocks are no longer bound to a certain
place, they have the drawback that the magnetic alternating field
is totally absent when no consumers are connected to the network,
which means if no current flows in these conductors. The then still
present electric stray field is frequently extremely weak and can
be received only by high sensitive and, in most instances,
direction depending aerials and can be employed only with
multi-stage amplifiers.
Aside from the fact that in view of the frequently employed
dischargers or by the increasing employment of controlled
semiconductors, no precise maxima or minima occur at the receiving
station, the building up of a suitable receiver still encounters
the following difficulties. In order to cope with the network stray
field, an amplifier with extreme high ohm input and high amplifying
factor has to be employed because the receiving voltage
considerably drops already at a distance of a few meters from the
network conductors. With the increase in the input resistance,
however, not only the alternating field sensitivity increases, but
also the sensitivity with regard to static fields and other
disturbing signals. The employed synthetic materials of various
types which are employed to an ever increasing extend have in part
high insulating properties and therefore can easily take high
static charges so that it is meaningless to increase the
sensitivity of the receiver still further. Relationship between
usefulness and disturbances can in this way not be improved.
It is, therefore, the primary object of this invention to provide a
clock which is adapted to be synchronized in a wireless manner
while avoiding the above mentioned drawbacks.
It is another object of this invention to provide a clock as set
forth in the preceding paragraph which makes use of the advantages
inherent to the stabile frequency of the alternating current
network which remains substantially uninfluenced by outside
disturbances and which, in spite of few technical means, will even
with undesirably high deviations of the network frequency and with
a complete failure of the network be operated further at high
precision.
These objects and other obbjects and advantages of the invention
will appear more clearly from the following specification, in
connection with the accompanying drawings, in which:
FIG. 1 shows a block circuit according to which a transmitter is
connected to a low frequency alternating current network.
FIG. 2, by means of a block circuit, illustrates the buildup of the
receiver.
FIG. 3 represents a circuit for the pulse comparison.
FIG. 4 represents a diagram for showing the course of the voltage
with the heretofore customary rectification.
FIG. 5 shows the course of the voltage which is realized by a
further development of the invention with regard to the transmitter
circuit.
FIG. 6 diagrammatically illustrates the electric circuit of the
transmitter.
FIG. 7 shows circuitry to illustrate a feed-back loop with features
usuable for the present invention.
The objects of the present invention have, with a clock of the
above mentioned type which is to be synchronized in a wireless
manner, been solved by the fact that a transmitter is connected to
the alternating current network, which transmitter generates a
magnetic and/or electric alternating field with a frequency which
is above the sound frequency which latter is modulated directly by
low frequency synchronizing signals derived from the network or is
modulated with a multiple of such low frequency synchronizing
signals. The invention is furthermore characterized in that the
signals in the receiver are after amplification and demodulation
conveyed to a loosely coupled pulse comparing circuit. This pulse
comparing circuit receives the pulse sequence to be compared with
the network frequency from an electromechanical pulse generator.
The mechanical resonator of said pulse generator is in resonance
with the synchronizing pulses and in this condition from the
amplified input signal of the receiver receives the energy for
maintaining its oscillation and for the synchronous drive of the
driving mechanism. The electromechanical pulse generator
disconnects itself each time from the synchronizing pulses and
alone takes over the timely control of the driving mechanism, when
the low frequency deviates by a determinable fraction from the
rated frequency or when the network frequency drops out
completely.
It has been found particularly advantageous when the mechanical
resonator which is employed in the receiver as pulse emitter has a
frequency of 100 cycles per second. In such an instance, the
frequency of the synchronizing pulses can in a simple manner be
obtained from the network by means of a rectifier bridge which
doubles the network frequency. The 100 cycles per second impulse
sequence is modulated with the carrier frequency and conveyed to
the transmitter aerial. The frequency of the transmitter should
expediently amount to 20 and 50 kilocycles per second in order that
on one hand it will be sufficiently far from the audible range and
on the other hand will be sufficiently low in order to keep away
from the range of influence the fundamental waves and first
harmonic vibrations from television transformers.
There has, however, been found that in view of the unavoidable
capacitive influences in the transmitter circuit, especially in
view of the amplifier capacity, the pulse lengths do not fully
become zero so that the minima received by the receiver are not
very strong. Therefore, it is a further object of this invention to
provide a transmitter which, while taking advantage of both sine
half waves of the useful alternating voltage as synchronizing
pulses between the individual pulses has sufficiently great keying
space so that the transmitting frequency at these points in its
amplitude approximately reaches the value zero.
This further object has been realized by the fact that the network
alternating voltage which is doubled as to its frequency by means
of a rectifier bridge is for purposes of modulation conveyed with
the carrier frequency to the transmitter through one or more
electric control means which allow the current to pass through only
when a voltage threshold value has been obtained.
In order to keep the technical equipment for the transmitter to a
minimum, as control element exediently a simple glow lamp is
employed, the ignition voltage of which advantageously is above
half the network voltage. The same effect may also be realized by
employing instead of the glow lamp, Zener diodes which in at least
two branches of the rectifier bridge are operated within their
Zener range, which Zener diodes likewise have a pronounced
breakdown voltage.
Referring now to the drawings in detail, the low frequency
alternating current network is designated with the reference
numeral 1, the frequency of which in all industrialized countries,
when considering a longer period of time, has a very satisfactory
constancy which is adapted at satisfactory precision to be used as
time standard for synchronizing clocks. In the impulse emitter 2
the alternating voltage of the network is rectified by means of a
bridge rectifier whereby pulses with the double network frequency
are obtained. These pulses are modulated in the modulator 3 at
carrier frequency which expediently has a value of from 20 to 50
kilocycles per second. In the described embodiment, it is assumed
that the transmitter frequency starts at 25 kilocycles per second.
The thus modulated pulses are conveyed to the transmitter coil of
the or antenna 4 which expediently is designed as vertically
arranged wave magnet and for the purpose of the present invention
has favorable propagation properties. In order to keep the current
consumption and the heat development as low as possible, electronic
elements including transistor diodes and Zener diodes as noted
subsequently herein are employed in the transmitter and receiver
circuit. In this way, so small dimensions of the transmitter are
obtained that the transmitter finds sufficient place in a housing
which as to size and shape corresponds to approximately a telephone
plug. In order when connecting the transmitter not to lose the
useful effect of the jack, the customary sockets for other devices
to be connected to the network may be arranged on the sides of the
housing. In the wave magnet, first of all, the magnetic stray field
is taken advantage of whereby the range of the transmitter can be
better limited and whereby also undesired over-the-horizon ranges
can be eliminated which would otherwise interfere in more remote
surroundings.
The receiver according to FIG. 2 likewise comprises vertically
arranged aerials of the wave magnet type, which conveys the
magnetic and/or electric field to the amplifier 6, amplifier 6
being built up of a plurality of transistorized amplifier stages.
In a feed-back branch of the amplifier there is arranged a filter 7
composed of RC-elements, for instance a double T filter, the
structural elements of which are so dimensioned that the maximum
damping of the filter will occur at the carrier frequency. In this
way, the selectivity of the or antenna 5 is increased and
interferences which may originate for instance from a 50 cycle per
second interference field are suppressed. Behind the demodulator 8
the desired synchronizing pulses are received which correspond to
the double network frequency.
All parts of the receiver shown in FIG. 2 including the aerial 5
can in view of their small size be arranged in a customary clock
housing. Such housing also contains the pulse generator 9 which
comprises primarily a mechanical resonator, the oscillation
frequency of which is tuned to the frequency of the newtwork. The
electric receiver circuit, the driving mechanism 11 for the
indicator 12 and the pulse generator 9 are all driven by a battery
in the clock. The pulse frequency generated in the pulse generator
9 and kept constant by the mechanical resonator is compared to the
frequency of the synchronizing pulses in the pulse comparing
circuit 10 which frequency is received by the transmitter.
FIG. 3 shows by way of a diagram, details of the pulse comparing
circuit 10 according to FIG. 2. At the base of the input transistor
20 there prevails the synchronizing signal of the network in the
form of comparatively short pulses so that the transistor 20 will
at a pulse frequency of 100 cycles per second be conductive for a
short time, said synchronizing signal having been received by the
transmitter and having been prepared in the receiver circuit. With
a coil 21 which is equipped with a tapping and which in its
entirety acts as a synchronizing coil, one coil section 21a serves
as driving coil whereas the other coil section 21b serves as
control coil for mechanical resonator 22. The transistor 20 drives
at a 100 cycle per second oscillation and through coil 21 the
mechanical oscillator which is preferably formed by a tuning fork.
By means of a non-illustrated magnetic coupling, the wheel 23 is
uniformly rotated synchronously with regard to the oscillating
frequency of the resonator 22 whereby the driving mechanism 11 of
the indicator 12 is driven. Coil 21 is preferably energized by the
synchronizing pulses when the tuning fork 22 oscillates through the
zero point. It is known that for maintaining this oscillation, as
long as oscillating synchronism prevails between the drive and the
mechanical resonator, only an extremely small quantity of energy is
required. To the end of the tuning fork 22 there is connected a
small permanent magnet 22a which in view of its oscillation induces
a small electromotoric force in the coil 21. If now, the frequency
of the pulses received from the network differs from the frequency
of the tuning fork 22, also the oscillation of the tuning fork is
no longer completely in resonance with the driving pulses. As a
result thereof, the energy of the synchronizing pulses will no
longer suffice for completely maintaining the oscillation of the
tuning fork 22. It is at this point that with increasing deviation
of the frequencies, the pulses of the working transistor 24 start
to an ever increasing extent. The working transistor is in the case
of synchronism, which means when the synchronizing pulses occur at
the right time with regard to the oscillation of the tuning fork
22. It is at this point that with increasing deviation of the
frequencies, the pulses of the working transistor 24 start to an
ever increasing extent. The working transistor is in the case of
synchronism, which means when the synchronizing pulses occur at the
right time with regard to the oscillation of the tuning fork,
blocked by the effect of the control transistor 25. The control
transistor 25 which has its base connected to the voltage divider
26, 27 furthermore brings about that the amplitude of the working
pulses is kept constant. These working pulses pass only to the
winding of the driving coil 21a. When the electromotoric force
generated in the control coil 21b increases, the control transistor
25 becomes conductive to greater extent whereby the condenser 29 is
short circuited. Inasmuch as the coil sections 21a and 21b are
coupled to each other , a condenser 30 is interposed between the
base and the collector of the transistor 24 whereby the circuit
will be prevented from working as a blocking oscillator. When the
frequency of the synchronizing pulses obtained from the network
differ considerably from the frequency of the tuning fork 22, and
if the network fails completely, the pulses for driving the tuning
fork 22 are generated by triggering the working transistor 24 which
pulses through driving coil section 21a go to minus. In this
connection, first the base of the transistor 24 is biased by the
resistor 28 whereby a small current flows through the emitter
junction and the driving coil section 21a. The electromotoric force
induced in the control coil 21b by the oscillation of the permanent
magnet 22a passes through the condenser 29 to the base of the
transistor 24 whereby the transistor is somewhat more modulated and
causes a somewhat stronger pulse to pass to the driving coil
section 21a. This is repeated several times in a very short time
until the full electromotoric force is obtained for maintaining the
oscillation of the tuning fork 22.
As long as the network frequency is identical to the frequency of
the pulse generator, the mechanical resonator and the driving
mechanism for the clock are driven for all practical purposes only
by the amplified input pulses of the receiver. If, however, the
frequency of the network 1 differs from the frequency of the pulse
emitter 9 beyond a permissible tolerance, which tolerance may be
set for instance for .+-. 0.15 cycles per second, the pulse
generator 9 of the receiver will at a frequency which is held
constant by the mechanical resonator, at increasing frequency
difference and with the electromotoric force remaining constant
take over the drive of the resonator and thereby of the clock. This
desired effect which corresponds to a loose coupling of the pulse
frequency generated by the pulse generator with the synchronizing
frequency received from the network in the receiver is obtained by
the fact that the mechanical resonator relative to the received
synchronizing pulses has a relatively high oscillation stability.
Moreover, the mechanical resonator has a highly integrating effect
whereby almost all interfering pulses are absorbed. In order to
keep the current consumption of the coil for the drive of the
mechanical resonator and of the driving mechanism as low as
possible, the pulse generator circuit is so designed that the coil
for driving the mechanical resonator is at least partially employed
for synchronizing the comparing pulses. Also, when the network
fails, the driving mechanism continues operating at its own
frequency which in view of the mechanical oscillator is so constant
that a deviation of the clock from the rated value will also over a
longer period of time remain within a permissible range.
As will be seen from FIG. 4, from the network alternating voltage
when employing a rectifying bridge, both half waves of the sine
oscillation are made use of so that the rectified pulse sequence
will have the double network frequency. The transmitter circuit,
especially the rectifier bridge has a capacitive influence upon the
shape of the pulse form which differs or deviates from the ideal
shape which is indicated by dash lines at 31. It will be evident
therefrom that the voltage value between the individual half waves
does not drop to zero so that also the carrier frequency at these
points does not have a clear and usuable minimum. As a reuslt
thereof, a reliable working of the receiver is not assured in every
respect for the precise time keeping of the clock which is
synchronizable in a wireless manner, it would be desirable that at
the receiver there were available a sufficiently wide key gap.
The curve of the transmitter pulses as obtained by the present
invention is shown in FIG. 5. According to FIG. 5, between the
pulses a sufficiently wide keying space 32 is formed by the
application of an electric control element which becomes current
conductive only when a certain voltage swell value has been
obtained, the amplitude of said keying space 32 equals or
approximately equals zero.
FIG. 6 shows the electric circuit of the transmitter according to
the invention. The transmitter 33 which is known per se generates a
carrier frequency of for instance 25 kilocycles per second which is
conveyed to a wave magnet 34. Connected to the alternating current
network is a rectifier bridge 35, at the outlet of which prevails
the voltage of the two rectified network sine half waves. This
pulse sequence has a frequency which equals twice the frequency of
the network. Between the rectifier bridge 35 and a tapping of the
transmitter coil 34 there is arranged an electric control element
36 which will let the current pass only when a certain voltage
swell value has been reached. According to the embodiment
illustrated in FIG. 6, this control element is represented by a
simple glow lamp 36. Expediently, the voltage of the glow lamp 36
is so selected that it is somewhat above the voltage of the
network. With these dimensions, a sufficiently wide key gap 32
(FIG. 5) is obtained without affecting the energy content of the
pulse. The same effect can also be realized when instead of the
glow lamp 36 Zener diodes 27 are provided in two branches of the
rectifier bridge in addition to the already present rectifier
diodes. This has to be effected in such a way that when viewed in
the forward direction of the rectifier diodes the Zener diodes are
operated in their Zener range.
By means of this simple step it is possible to modulate the
transmitter in the pulse intervals to zero so that also at short
distances between transmitter and receiver a pulse gap on the
receiver will be noticeable and that during the demodulation no
difficulties are encountered. When the ignition voltage of the glow
lamp is selected for instance at 120 volts, the transmitter will
become effective only at approximately sin..alpha. = 23.degree. so
that the unavoidable capacities can have no disadvantageous
effect.
In the U.S. The network frequency is set to 60 Hz. In Europe the
network frequency, however, is mostly 50 Hz. In order to come from
this 50 Hz-frequency to the 100 Hz-frequency, there can be used a
known rectifying bridge that is known to double frequency. Such a
rectifying bridge is shown in FIG. 6 at the right bottom location
thereof.
If one proceeds from a network frequency of 60 Hz, it is
advantageous if the receiver used as a mechanical oscillator as the
impulse giving means provides a frequency of 120 Hz. It is possible
again to work for this purpose with the same known bridge
rectification circuit. The description proceeds collectively from a
network frequency of 50 Hz. However, nothing changes with respect
to the basic manner of operation when operating with a network
frequency of 60 Hz. The German word "Tastluecke" means time spacing
between the individual sending impulses. In this "Tastluecke" or
literally "feeler gap" or condition the sender amplitude is null.
The wording "keying space" also would be the correct in translation
for "Tastluecke."
In order to maintain the current use and heat development as small
as possible, there are electronic construction elements such as
transistor diodes and Zener diodes used in the sender and receiver
circuitry as shown in FIGS. 3 and 6.
The return coupling loop with the filter 7 is so constructed as
shown by FIG. 7. Transistor 20 is a pnp transistor.
As to the manner of function of the inventive circuitry the
following statements can be made. There is to be proceeded
therefrom that there lies or exists on the emitter of the
transistor 25 on the one hand the generated EMK or electromotive
force generated in the coil 21b through the swinging of the tuning
fork means 22, 22a and on the other hand the synchronizing impulse
coming by way of the transistor 20. The EMK has a sinusoidal-form
shape with a positive and a negative half wave or cycle. In the
case of synchronous running form impulse and swinging of the tuning
fork, the impulse (which is positive) falls together with the
parting line of the positive half wave and is superimposed upon the
same.
During the positive half wave of the EMK generated in the coil 21b
the transistor 25 is blocked which means the same represents a high
resistance. During the negative half wave the transistor 25 is more
or less strongly conductive so that the condenser is more or less
shorted.
If the frequencies of the impulses and the tuning fork means
diverge only so little from each other that the impulse still
occurs at the time of the positive half wave of the EMK, then the
pulse partially reaches the base of the working transistor 24 and
switches the same so that the current which flows through the drive
coil 21a becomes amplified.
If the frequencies of the impulse and the EMK diverge further
strongly from each other that the impulse occurs at a time in which
the EMK is passing through the negative half wave, then the impulse
blocks the transistor 25 and comes again by way of the condenser 29
to the base of the working transistor 24. This becomes conductive
and the drive coil 21a at the time of the impulse has an additional
current flowing therethrough. This amplified or strengthened
current flow through the coil 21a repeats itself with each arriving
impulse so long until the frequency of the tuning fork means
corresponds with that of the arriving impulses.
If the network and thereby the arriving impulses completely drop
out, so the impulses are generated for the drive of the tuning fork
alone through the guidance or control of the working transistor 24.
The base of the transistor 24 is preconnected by way of the
resistance 28 whereby a small current flows over the emitter
distance and the drive coil 21a. The EMK induced in the control
coil 21b reaches with the positive half waves thereof while the
operation of the transistor 25 is blocked by way of the condenser
29 again to the base of the transistor 24. Thereby, current flows
through the drive coil 21a. Also in this case, there is maintained
accordingly the swinging of the tuning fork.
The sender 33 in FIG. 6 represents a transistor circuit with a
sending coil 34 of conventional or known type. The carrier wave
generated from the transistor circuit is modulated with the signal
generated by the rectifier 35 in a conventional manner by way of
superimposing of both frequencies.
The receiver in FIG. 2 provides a known amplifier 6 and a known
demodulator 8. Both are formed by transistor circuits known in
themselves. In FIG. 7 there is illustrated the circuit of the
receiver 6, the filter 7 and the demodulator 8. In FIG. 7 the
corresponding circuit parts are designated with these identifying
numerals.
In FIG. 7 there is illustrated an electrical circuit in which the
amplifier 6, the filter 7 and the demodulator are suitably
arranged. At the input of the amplifier 6 there is arranged a
receiver circuit or antenna 5 consisting of a condenser 38 and a
coil 39. A first transistor 41 is supplied by way of a signal
emitted from a sender or transmitter according to FIG. 6 by way of
a condenser 40. The amplifier 6 is formed by a two-step transistor
circuit which operates with the transistors 41 and 42. The
resistances of this amplifier circuit are designated with the
reference numerals 43, 44, 46', 46, 47. The emitters of the
transistors lie upon mass or ground. The collectors of the
transistors lie above the resistances 44 and 46 on the positive
pole of the battery. The condensers 48 and 49 serve for coupling.
The condenser 49 couples the collector of the transistor 41 onto
the base of the transistor 42; the condenser 48 couples the
collector of the transistor 42 onto a transistor 50 of the filter
circuit 7. The filter circuit consists of the transistors 50 and 51
and provides resistances 52, 53, 54, 55 and 56. The collector of
the transistor 50 lies on the one hand above the resistance 52 on
the positive pole of the battery. On the other hand, the base of
the transistor 51 lies on the collector. The emitter of the
transistor 51 represents the output of the filter circuit 7 leading
to the demodulator 8 and the same is connected by way of the
emitter-resistance 53 to mass or ground. Simultaneously, there is a
double-T-filter engaging on the emitter of the transistor 51 and
one filter branch thereof is formed by the resistances 54 and 55
and by the condenser 59 and the other branch thereof is formed by
the condensers 57, 58 and the resistance 56. The resistance 56 and
the condenser 59 lie or engage with an end thereof on the mass or
ground.
The demodulator is connected to the filter circuit 7 by way of a
condenser 60. The same provides two transistors 61 and 62. The
resistances of the demodulator are designated with the reference
numerals 63, 64, 65, 66, 67 and the condensers thereof are
designated by the reference numerals 68, 69, 70. On the basis of
the transistor 61, there is connected the condenser 60. The base of
the transistor 62 is connected with a potentiometer consisting of
resistances 63 and 64 and the same is coupled by way of the
condenser 68 to the collector of the transistor 61. The collectors
of the transistors 61 and 62 lie over the resistances 65,
respectively, 66 on the positive pole of the battery. The emitter
lies upon the mass or ground. The resistance 66 is connected
parallel to the condenser 69. On the collector of the transistor 62
there is connected a return coupling branch which provides a
condenser 71 and a resistance 72 and leading by way of the
resistance 45 to the base of the transistor 42.
The collector of the transistor 62 lies over the condenser 70 on a
potentiometer consisting of the resistance 67 and a resistance 73.
A transistor 20 is also connected to this potentiometer. The
polarity of the transistor 20 is the reverse of that of the other
transistors. The circuit connection of the transistor 20 and the
further construction elements was described in detail already
previously. The reference numerals pertaining thereto are the same
as in FIG. 3.
The means which modulate the carrier wave of the sender are the
rectifier bridge circuit and the connection thereof with the sender
coil whereby the connection with the sending coil especially occurs
by way of the circuit as characterized by the following:
The transmitter includes current controlling means in circuit with
rectifier means.
The current controlling means is in series with rectifier
means.
The current controlling means is in the form of a glow lamp having
an ignition voltage which is about half of the normal network
voltage.
The demodulation occurs in a receiver in a conventional manner by
way of a known circuit which is illustrated in FIG. 7 mentioned
earlier.
FIG. 2 illustrates a schematic diagram or block circuit in which
the amplifier 6, the filter 7 and the demodulator 8 are connected
sequentially in series. Such circuitry can also be illustrated as
though the amplifier 6 were connected directly with the demodulator
8. With reference thereto, however, there must be noted that such
direct connection would not be entirely correct and justified. Both
right transistors of the receiver 6 actually would already be
considered to be attributed to the filter 7 and particularly on the
basis of the manner of function of this filter. This is
particularly so constructed that return coupling or feed back is
provided so that frequencies appearing at the emitter of the right
transistor encounter a resistance 15 k .OMEGA. upon the input at
the left of both right transistors and particularly in a manner
that all those frequencies which are located adjoining the desired
frequency are permitted to pass and thus being given as counter
coupling upon the input of the left transistor, whereas the desired
frequencies are expressed and accordingly no counter-coupled signal
is applied to this transistor. In this manner, only those
frequencies appear on the left transistor of the demodulator 8 that
are desired for the results being sought. The input of the left of
both right transistors of the receiver 6 is provided by way of a
condenser on the output of the transistor T2 which together with a
further transistor preconnected therewith forms the actual receiver
amplifier means.
In summary with respect to the foregoing, those statements are
better and more understandable that are directed thereto that the
receiver 6 consists of the receiver circuit illustrated entirely to
the left in the drawing as well as the amplifier including both
left transistors. The filter 7 inclusive with both aforementioned
transistors are arranged subsequent to this receiver 6 and arranged
thereafter finally is the demodulator 8 in the form as illustrated
in the drawing. Thus, the illustration of the receiver 6 should
provide sufficient disclosure thereof to accomplish the functions
as involved herewith.
With respect to a signal in response to deviation of the network
frequency by a predetermined amount from the rated frequency
thereof, there can be set forth as to the source of said signal an
explanation of the corresponding part of the collective manner of
operation. There is to be understood that in the circuit there is
not necessarily generated a separate signal in order to make the
electrical oscillator so-called operative or inoperative. There is
much more involved the fine distinction that by way of the
transistor 20 there is an impulse, namely the synchronizing impulse
as to the oscillator circuit, in other words, transistors 24, 25,
control coil 22b and operating coil 21a as well as tuning fork 22
being given whereby the automatic control or self-regulation of the
oscillator circuit is dependent thereon as to amplitude thereof in
which measure these synchronizing impulses are synchronously in
phase with the automatic control or self-regulating impulses of the
oscillator circuit. The circuitry operates thereby in the manner
that with existing synchronization there suffices the synchronizing
impulse already delivered by way of the transistor 20 to supply the
necessary current to the driving or operating coil 21a. By way of
the simultaneously applied corresponding positive potential at the
upper terminal or clamp of the control coil section 21b, there is
generated in the emitter-base circuit of the working transistor 24
such a collective potential that this transistor now is only
"partially" conducting, in other words, this transistor gives off a
weak current by way of the emitter thereof to the drive coil
section 21a.
If in contrast there exists no complete synchronization between the
synchronizing impulses of the transistor 20 and the automatic
control or self-regulating impulses of the oscillator, so during
the time while the synchronizing impulses and the automatic control
or self-regulating impulses do not coincide, the transistor 24 is
controlled or regulated to conduct further and delivers a higher
current to the working coil section 21a than would be the case
during coincidence of both impulses at a time. In this manner,
there is assured that the summation of the current generated by way
of the synchronizing impulses are by way of the automatic control
or self-regulating impulses in the working coil section 21a as a
result always equal regardless of whether phase synchronization
exists or not.
It is, of course, to be understood that the present invention is,
by no means limited to the specific showing in the drawings, but
also comprises any modifications within the scope of the appended
claims.
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