U.S. patent application number 11/051876 was filed with the patent office on 2005-08-04 for radio control system for models.
Invention is credited to Yamamoto, Michio.
Application Number | 20050170787 11/051876 |
Document ID | / |
Family ID | 34805895 |
Filed Date | 2005-08-04 |
United States Patent
Application |
20050170787 |
Kind Code |
A1 |
Yamamoto, Michio |
August 4, 2005 |
Radio control system for models
Abstract
In conventional radio controlled models, a receive frequency is
changed with a changeover switch mounted in a receiver body. In the
present invention, a frequency switching scheme, employing a radio
system in which a transmitter switches the receive frequency, is
provided. Using weak radio waves usable without authorization, the
transmitter transmits frequency data set therein as a frequency
switching signal to a receiver. In the receiver, the receive
frequency is set to a predetermined weak radio wave frequency when
the power source is turned on. Upon receiving the weak radio waves,
the receiver reads the frequency data out of the set signal and
stores it into the memory means. Thus, the frequency setting has
been completed. When the receiver does not receive the frequency
switching signal for a fixed period of time, it reads out the
frequency data used previously from the data memory to start the
receiving operation.
Inventors: |
Yamamoto, Michio;
(Mobara-shi, JP) |
Correspondence
Address: |
QUARLES & BRADY LLP
411 E. WISCONSIN AVENUE
SUITE 2040
MILWAUKEE
WI
53202-4497
US
|
Family ID: |
34805895 |
Appl. No.: |
11/051876 |
Filed: |
February 4, 2005 |
Current U.S.
Class: |
455/70 |
Current CPC
Class: |
A63H 19/24 20130101;
A63H 30/04 20130101; H04B 17/391 20150115 |
Class at
Publication: |
455/070 |
International
Class: |
H04B 017/00; H04B
001/00; H04B 007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 4, 2004 |
JP |
2004-027864 |
Claims
What is claimed is:
1. A radio control system for models, comprising, a transmitter and
a receiver, in a frequency synthesizer scheme using a PLL circuit;
said radio control system being capable of selecting a first
frequency from among a group of frequencies when a radio model is
operated, said first frequency being set as a transmission
frequency of said transmitter and as a receiving frequency of said
receiver, said frequency group being predetermined as usable
frequencies when transmits and receives an operation signal for
manipulating a radio controlled model; wherein, in order to set a
transmission frequency of said transmitter and a receiving
frequency of said receiver to said first frequency, said
transmitter transmits a frequency set signal containing information
on said first frequency to said receiver, a transmission frequency
of said frequency set signal being set to a second frequency
different from said first frequency; wherein said receiver
previously sets a receiving frequency to said second frequency, and
sets, after receiving said frequency set signal, sets said
receiving frequency to said first frequency from among said group
of frequencies based on said frequency set signal; wherein said
transmitter transmits said operation signal with said first
frequency after a receiving frequency of said receiver is set to
said first frequency; wherein said receiver receives said operation
signal to manipulate said radio controlled model.
2. The radio control system for models defined in claim 1, wherein
said transmitter sets a transmission signal to said second
frequency at power-on and then transmits said frequency set signal
to said receiver; and wherein said receiver sets a receiving
frequency to said second frequency at power-on and thus can receive
said frequency set signal.
3. The radio control system for models defined in claim 1, wherein
said receiver sets a receiving frequency to said second frequency
for only a constant period of time at power-on.
4. The radio control system for models defined in claim 1, wherein
said transmitter uses said second frequency and uses weak radio
waves usable without authorization when transmitting said frequency
set signal containing information on said first frequency to said
receiver.
5. A radio control system for models, comprising: a transmitter and
a receiver, in a frequency synthesizer scheme using a PLL circuit;
said radio control system being capable of selecting a first
frequency from among a group of frequencies when a radio model is
operated, said first frequency being set as a transmission
frequency of said transmitter and as a receiving frequency of said
receiver, said frequency group being predetermined as usable
frequencies when transmits and receives an operation signal for
manipulating a radio controlled model; said transmitter including:
operation signal generator means for generating said operation
signal by an operation of an operation section; frequency set
signal generator means for generating a frequency set signal
corresponding to said first frequency selected from among said
group of frequencies; memory means for storing first frequency data
corresponding to said first frequency and second frequency data
corresponding to a second frequency different from said first
frequency set as a transmission frequency when said frequency set
signal is transmitted; frequency switching controller means for
reading out said second frequency data from said memory means and
outputting said frequency set signal from said frequency set signal
generator means or for reading out said first frequency data from
said memory means based on said frequency set signal and outputting
said operation signal from said operation signal generator means;
transmission frequency setting means for setting a transmission
frequency based on first frequency data or second frequency data
read out from said memory means; and signal transmitter means for
transmitting said frequency set signal or said operation signal,
with a transmission frequency set by said transmission frequency
setting means; said receiver including: memory means for storing
said first frequency data and said second frequency data; frequency
switching controller means for reading out said second frequency
data and said first frequency data based on said frequency signal
transmitted from said transmitter, out of said memory means;
receiving frequency setting means for setting a receiving frequency
based on said first frequency data or said second frequency data
read out from said frequency switching controller means; and signal
receiver means for receiving said frequency set signal or said
operation signal transmitted from said transmitter, with a
receiving frequency set by said receiving frequency setting
means.
6. A radio control system for models defined in claim 5, wherein
said signal transmitter means controls transmission power of radio
waves transmitted based on a command from said frequency setting
controller means when transmitting said frequency setting signal.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a radio control device
(gear) for remotely manipulating radio controlled models.
[0002] Nowadays, radio-control devices (hereinafter referred to as
R/C device) are used for various radio controlled models
(hereinafter referred to as R/C models) such as model aircraft,
model helicopters, model vehicles, model boats and others. For
them, two types of main carrier wave modulation scheme, that is, AM
(Amplitude Modulation) and FM (Frequency Modulation) are used or
two types of main carrier wave modulation signal conversion scheme,
that is, PPM (Pulse Position Modulation) and PCM (Pulse Code
Modulation) are used.
[0003] Regarding the R/C devices, the frequency bands for carriers
and frequencies in each frequency band, allowable in each country,
are regulated by the Radio Law. For example, the frequency bands
usable in Japan are 27 MHz band, 40 MHz band, and 72 MHz band, each
in which plural frequencies are determined.
[0004] When plural radio controlled models are used in the same
area at the same time, the frequency not used by other radio
controlled models must be selected because of avoidance of
interference. At this time, the method is used of exchanging the
crystal oscillator (referred to as qualtz) to select a different
band and changing the carrier frequency.
[0005] Recently, the frequency synthesizer scheme employing the PLL
(Phase Locked Loop) circuit generally used in the communication
fields is broadly used. Such a frequency synthesizer scheme can set
the carrier to different frequencies by changing the frequency
division ratio.
[0006] However, the use of the R/C device in the frequency
synthesizer scheme depends on regulation by the Radio Law in each
country. Moreover, even in countries allowing the use of the
frequency synthesizer scheme, frequencies other than designated
frequencies cannot be used.
[0007] Japanese Utility Model publication No. Zikkai-hei 6-31232,
filed by the present applicant, discloses a conventional
transmitter to solve the above-mentioned problem.
[0008] The transmitter has the configuration in which a crystal
high-frequency module or a PLL high-frequency module is attachable
to or detachable from the transmitter. For that reason; in
countries applying and not applying the frequency synthesizer
scheme in compliance with different legal systems, a common
transmitter can be used without preparing different
transmitters.
[0009] The PLL high-frequency module has the memory that stores
frequency data to variably control the carrier wave frequency.
Hence, when high-frequency modules, each having a memory that
stores frequency data by country, are prepared, the frequency
synthesizer scheme using a carrier wave of a predetermined
frequency can be applied for the transmitter through an exchange of
the module.
[0010] In the receiver, the crystal oscillator is replaced to avoid
the interference of receiving frequencies possible in the same
area, in a manner similar that of the transmitter. However, since
spare crystal oscillators have to be always carried, receivers in a
frequency synthesizer scheme, each incorporating a PLL circuit, are
being used widely.
[0011] In that receiver, the frequency can be easily changed and
adjusted by varying the frequency division ratio of the frequency
divider through a changeover operation of a DIP switch disposed in
the receiver body. However, while the radio controlled model is
operating, the switch may change due to a function of some kind
such as the vibration of an engine, thus varying the frequency
division ratio. Finally, the receiving frequency is switched over
so that the radio-controlled model becomes uncontrollable.
[0012] In order to solve such a problem, Japanese Utility Model No.
Tokkai-hei 9-9697, filed by the present applicant, discloses a
receiver for radio controlled models in a frequency synthesizer
scheme using a conventional PLL circuit.
[0013] In the receiver, two DIP switches, for example, which are
disposed therein, selects a predetermined frequency from among
predetermined plural sets of frequency data. When the power source
is turned on, the receiver checks a usable frequency group and then
captures the selected band information. The receiver determines
whether or not the frequency data corresponding to the band
information is a normal frequency. In the discrimination result,
the frequency division ratio of the frequency divider in the PLL
circuit is determined based on the frequency data stored in the
memory. The frequency locked on based on the frequency division
ratio is set to a fixed value as a receiving frequency until the
power source is turned off at the next stage. For that reason, the
possibility does not occur that the receiving frequency once set
changes intentionally due to disturbance such as the vibration or
erroneous operation. As a result, the reliability can be
improved.
[0014] In the radio controlled model in the frequency synthesizer
scheme incorporating a PLL circuit, the receiver mounted in the
radio controlled model is taken out to vary, for example, the
receiving frequency. The switch such as a DIP switch disposed in
the receiver body is manually operated to change the frequency
division ratio. Thus the receiving frequency is changed.
[0015] The switch is disposed in the housing of the radio
controlled model while the receiver is wrapped or covered with a
vibration-proof and water-proof rubber. Thus, a change of receiving
frequency data or a failure of the radio controlled model, caused
by due to changeover of the switch of the receiver due to damages
such as vibrations of the engine added to the model body or water
leakage, is prevented.
[0016] Such a configuration has a disadvantage in the frequency
changing work. That is, when the receiving frequency is forced to
change because a set frequency has been already used, the receiver
is first taken out of the radio controlled model. Then, the
vibration-proof or water-proof material such as rubber is uncovered
to perform the frequency switching work. Finally, the receiver is
again covered with the rubber and is stored inside the radio
controlled model. This is troublesome and results in a time
loss.
SUMMARY OF THE INVENTION
[0017] The present invention is made to solve the above-mentioned
problems.
[0018] An object of the present invention is to provide a radio
control system for models, which can simply switch the receiving
frequency of a receiver, without taking out the receiver mounted in
a radio model.
[0019] In an aspect of the present invention, a radio control
system for models, comprises a transmitter and a receiver, in a
frequency synthesizer scheme using a PLL circuit; the radio control
system being capable of selecting a first frequency from among a
group of frequencies when a radio model is operated, the first
frequency being set as a transmission frequency of the transmitter
and as a receiving frequency of the receiver, the frequency group
being predetermined as usable frequencies when transmits and
receives an operation signal for manipulating a radio controlled
model; wherein, in order to set a transmission frequency of the
transmitter and a receiving frequency of the receiver to the first
frequency, the transmitter transmits a frequency set signal
containing information on the first frequency to the receiver, a
transmission frequency of the frequency set signal being set to a
second frequency different from the first frequency.
[0020] The receiver previously sets a receiving frequency to the
second frequency, and sets, after receiving the frequency set
signal, sets the receiving frequency to the first frequency from
among the group of frequencies based on the frequency set signal.
The transmitter transmits the operation signal with the first
frequency after a receiving frequency of the receiver is set to the
first frequency. The receiver receives the operation signal to
manipulate the radio controlled model.
[0021] Moreover, the transmitter sets a transmission signal to the
second frequency at power-on and then transmits the frequency set
signal to the receiver. The receiver sets a receiving frequency to
the second frequency at power-on and thus can receive the frequency
set signal. The receiver sets a receiving frequency to the second
frequency for only a constant period of time at power-on.
[0022] Moreover, the transmitter uses the second frequency and uses
weak radio waves usable without authorization when transmitting the
frequency set signal containing information on the first frequency
to the receiver.
[0023] In another aspect of the present invention, the transmitter
includes operation signal generator means for generating the
operation signal by an operation of an operation section; frequency
set signal generator means for generating a frequency set signal
corresponding to the first frequency selected from among the group
of frequencies; memory means for storing first frequency data
corresponding to the first frequency and second frequency data
corresponding to a second frequency different from the first
frequency set as a transmission frequency when the frequency set
signal is transmitted; frequency switching controller means for
reading out the second frequency data from the memory means and
outputting the frequency set signal from the frequency set signal
generator means or for reading out the first frequency data from
the memory means based on the frequency set signal and outputting
the operation signal from the operation signal generator means;
transmission frequency setting means for setting a transmission
frequency based on first frequency data or second frequency data
read out from the memory means; and signal transmitter means for
transmitting the frequency set signal or the operation signal, with
a transmission frequency set by the transmission frequency setting
means.
[0024] The signal transmitter means controls transmission power of
radio waves transmitted based on a command from the frequency
setting controller means when transmitting the frequency setting
signal.
[0025] The receiver includes memory means for storing the first
frequency data and the second frequency data; frequency switching
controller means for reading out the second frequency data and the
first frequency data based on the frequency signal transmitted from
the transmitter, out of the memory means; receiving frequency
setting means for setting a receiving frequency based on the first
frequency data or the second frequency data read out from the
frequency switching controller means; and signal receiver means for
receiving the frequency set signal or the operation signal
transmitted from the transmitter, with a receiving frequency set by
the receiving frequency setting means.
[0026] The present invention employs a frequency switching scheme
in compliance with the radio scheme capable of switching the
frequency from the transmitter side, without taking the receiver
out of the inside of a radio controlled model. This can eliminate
the frequency switching work and time loss. For that reason, the
user can comfortably enjoy playing with a radio controlled
model.
[0027] Moreover, in the frequency setting, the frequency switching
signal is transmitted and received using weak radio waves so that
the frequency selection is preformed arbitrarily. Using for weak
radio waves a frequency, which is different from the frequency used
in the radio control device, allows preventing interference to
other radio controlled models.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] This and other objects, features, and advantages of the
present invention will become more apparent upon reading of the
following detailed description and drawings, in which:
[0029] FIG. 1(a) is a block diagram schematically illustrating a
transmitter, according to an embodiment of the present
invention;
[0030] FIG. 1(b) is a block diagram schematically illustrating a
receiver, according to the embodiment of the present invention;
[0031] FIG. 2 is a flowchart illustrating the operation of the
transmitter; and
[0032] FIG. 3 is a flowchart illustrating the operation of the
receiver.
DESCRIPTION OF THE EMBODIMENTS
[0033] A radio control system according to an embodiment of the
present invention will be explained by referring to the attached
drawings.
[0034] FIG. 1 is a block diagram illustrating a radio control
system according to an embodiment of the present invention. FIG.
1(a) is a block diagram illustrating a transmitter and FIG. 1(b) is
a block diagram illustrating a receiver.
[0035] The transmitter and the receiver are explained below
respectively.
[0036] Transmitter:
[0037] In the embodiment of FIG. 1(a), the transmitter 1 includes
frequency set signal generator means 2, operation signal generator
means 3, frequency switching controller means 4, transmission
frequency setting means 6, signal transmitter means 7, memory means
8, and modulation signal generator 5.
[0038] As shown in FIG. 1(a), the frequency set signal generator
means 2 includes a frequency set signal generator 2a. The operation
signal generator means 3 includes an operation signal generator 3a.
The frequency switching controller means 4 includes a frequency
switching controller 4a. The transmission frequency setting means 6
includes a frequency controller 6a and a frequency synthesizer
6b.
[0039] The signal transmitter means 7 consists of a high-frequency
amplifier 7a, a power controller 7b, a power amplifier 7c, and a
transmitter antenna 7b. The memory means 8 includes a memory
8a.
[0040] The transmitter operates differently in a frequency setting
mode (a power-on time) which indicates the time when the
transmitter is powered on and in an operation mode (a normal
operation time) which indicates the time when a normal radio
control is operated. The mode changeover switch (not shown), which
is attached to the transmitter, can suitably operated to change
over the mode. The operation in each mode of each operational
element will be explained below.
[0041] The memory 8a, which is a data signal rewritable memory,
previously stores frequency data corresponding to each country and
ID information added to the receiver.
[0042] The frequency set signal generator 2a operates at a power-on
time. When a set key, for example, a rotary switch, which attached
to the transmitter is operated or rotated to set (or select) the
band information corresponding to a predetermined frequency. Thus,
the frequency set signal generator 2a generates the frequency set
signal (a frequency switching signal) corresponding to the band
information set at that time and then outputs it to the frequency
switching controller 4a.
[0043] As to the set key, which is attached in the place not
adversely affecting the operation of an operation stick on the
transmitter 1, can be arbitrarily determined in its mounting
position and shape.
[0044] The operation signal generator 3a operates in a normal
operation time. The operation signal generator 3a converts an
operation signal from an analog signal to a digital signal and then
outputs it to the frequency switching controller 4a. The operation
signal corresponds to an operation amount or ON/OFF of an operation
stick or each switch, attached corresponding to each channel in the
transmitter.
[0045] The frequency switching controller 4a performs the following
three operations at a power-on time. That is, (a) The frequency
switching controller 4a reads frequency data for weak radio waves
out of the memory 8a and then outputs it to the frequency
controller 6a.
[0046] (b) The frequency switching controller 4a outputs a power
control signal for weak radio waves to the power amplifier 7b.
[0047] (c) The frequency switching controller 4a outputs a
frequency set signal from the frequency set signal generator 2a to
the modulation signal generator 5.
[0048] In a normal operation, the frequency switching controller 4a
reads frequency data (frequency data for operation signal
transmission) corresponding to a frequency set signal input from
the frequency set signal generator 2a at a power-on time, out of
the memory 8a and then outputs it to the frequency controller 6a.
The frequency switching controller 4a outputs an operation signal
from the operation signal generator 3a to the modulation signal
generator 5.
[0049] The term, weak radio waves, means a feeble radio output
usable without authorization. Because the weak radio waves are set
to a given frequency, a frequency different from the frequency used
for the radio control device can be used so as not to interfere the
radio controlled model manipulated with other radio controlled
device. For that reason, frequencies which are not used for the
radio control device are previously set for weak radio waves and
are stored in the memory 8a and the data memory 22a, which is
memory means 22 in the receiver (to be described later).
[0050] Plural frequencies for weak radio waves may be stored in the
memory 8a and the data memory 22a. The user may select the
frequency suitable for the use environment. In that case, the
switch that selects the frequency for weak radio waves is attached
to the transmitter and the receiver, so that a frequency for weak
radio waves can be selected by suitably operating the switch.
[0051] Frequencies other than frequencies used in the radio control
device can be used arbitrarily. Actually, respective operation
elements have to be standardized to avoid a large sized or
complicated radio controlled device. For that reason, it is
preferable to use the frequency very close to the frequency band,
which is allowed to use for radio control devices.
[0052] The modulation signal generator 5 modulates the frequency
set signal output from the frequency switching controller 4a at a
power-on time and outputs the modulated frequency signal to the
frequency controller 6a. Moreover, at a normal operation, the
modulation signal generator 5 modulates an operation signal output
from the frequency switching controller 4a and outputs the
modulated operation signal to the frequency controller 6a.
[0053] The frequency controller 6a performs lock-on of the
oscillator frequency of the frequency synthesizer 6b at a power-on
time, based on the frequency data for weak radio waves output from
the frequency switching controller 4a. The frequency controller 6a
controls the modulation signal generator 5 to output the frequency
set signal to the frequency synthesizer 6b.
[0054] In a normal operation, the frequency controller 6a locks on
the oscillation frequency of the frequency synthesizer 6b, based on
the frequency data output from the frequency switching controller
4a. The frequency controller 6a controls the modulation signal
generator 5 to output the operation signal to the frequency
synthesizer 6b.
[0055] At a power-on time, the frequency synthesizer 6b oscillates
the frequency set signal input from the modulation signal generator
5 through the frequency controller 6a at a frequency locked on by
the frequency controller 6a and then outputs it to the
high-frequency amplifier 7a.
[0056] In normal operation, the frequency synthesizer 6b oscillates
the operation signal input from the modulation signal generator 5
through the frequency controller 6a at a frequency locked on by the
frequency controller 6a and then outputs it to the high-frequency
amplifier 7a.
[0057] The high-frequency amplifier 7a amplifies the frequency set
signal output from the frequency synthesizer 6b at a power-on time
and outputs it to the power amplifier 7c.
[0058] In normal operation, the high-frequency amplifier 7a
amplifies the operation signal output from the frequency
synthesizer 6b and outputs it to the power amplifier 7c.
[0059] The power controller 7b operates at a power-on time and
controls the output of the power amplifier 7c to be within
specified values of weak radio waves according to the power control
signal for weak radio waves input from the frequency switching
controller 4a.
[0060] The power amplifier 7b amplifies the frequency set signal
input from the high-frequency amplifier 7a at a power-on time,
based on the power control signal for weak radio waves to the power
controller 7b, and transmits it as a frequency set signal using
weak radio waves to the transmitter antenna 7d.
[0061] In normal operation, the power amplifier 7b amplifies an
operation signal input from the high-frequency amplifier 7a within
a specified value of radio waves usable when the radio controlled
model is manipulated, and thus transmits it as operation data to
the transmitter antenna 7d.
[0062] Next, the operation of the transmitter will be described
below by referring to the flowchart in FIG. 2.
[0063] First, when the set key provided to the transmitter is set
to a predetermined frequency (band), the transmitter is powered on.
Thus, the transmitter outputs a frequency set signal according to
the frequency (band) set by the frequency set signal generator 2a
(siol).
[0064] Next, the frequency switching controller 4a checks the
operation mode (S102). In the frequency set mode (S103), the
frequency switching controller 4a determines whether or not the
frequency set mode (S103) is a power-on time (Yes in S103) or a
normal operation time (No in S103).
[0065] At the power-on time (Yes in S103), the frequency switching
controller 4a adds the ID code read out of the memory 8a to the
frequency data (first frequency data) selected from the memory 8a
and modulates the result and then outputs it as the frequency set
signal.
[0066] Moreover, the frequency data for weak radio waves (second
frequency data) is read out of the memory 8a. The frequency
controller 6a locks on the oscillation frequency of the frequency
synthesizer 6b based on the frequency data for weak radio waves.
The frequency set signal is oscillated with the locked-on frequency
(a second frequency). The high frequency amplifier 7a amplifies the
frequency set signal. The power controller 7c controls the
frequency set signal to be within a specified value according to
the power control signal for weak radio waves from the frequency
switching controller 4a (S104).
[0067] The ID code to be added means a code for preventing an
erroneous operation in the use of the same radio devices. A device
identification code, that is, an ID code, is added to the
transmitter/receiver system. Thus, the transmitter and the receiver
can operate only by using the same identification code. In more
detail, the transmitter of the present embodiment includes plural
memories, each which previously stores an ID code set for each
receiver. The ID code can be changed according to an opponent
receiver. Therefore, in radio devices made in compliance with the
same specification, a single transmitter can deal with plural
receivers, each having a different ID code. This feature improves
the convenience of users. Here, the method of using ID codes has
been described but any erroneous recognition prevention method may
be used.
[0068] In the normal operation (No in S103), the voltage (in an
analog value) of a potentiometer connected to the stick or switch
provided corresponding to each channel of the transmitter is
converted into a digital signal acting as an operation signal and
then the operation signal is modulated. The oscillation frequency
of the frequency synthesizer is locked on based on the selected
frequency data (first frequency). The operation signal is
oscillated with the frequency locked on by the frequency
synthesizer 6b. the high-frequency amplifier 7a amplifies the
operation signal and then outputs it as a high frequency signal
(S105).
[0069] Then, the power amplifier 7b amplifies the high frequency
signal. The transmitter antenna 7d transmits the frequency set
signal or the operation signal. Thereafter, the operational flow
returns to the operation mode checking step (S106).
[0070] That operation is repeated until the power source is turned
off or the battery becomes dead.
[0071] Receiver:
[0072] In the embodiment shown in FIG. 1(b), the receiver 20
includes frequency switching controller means 21, memory means 22,
receiving frequency setting means 23, signal receiver means 24, and
frequency set signal decoder 25.
[0073] As shown in FIG. 1(b), the frequency switching controller
means 21 includes a frequency switching controller 21a. The memory
means 22 includes a memory 22a. The receiving frequency setting
means 23 includes a frequency controller 23a and a frequency
synthesizer and 23b. The signal receiver means 24 consists of a
high-frequency amplifier 24a, a frequency converter 24b, a decoder
24c, and a receiver antenna 24d.
[0074] Like the transmitter, the receiver operates differently in a
frequency setting mode (a power-on time) and in an operation mode
(a normal operation time). The operation of each operation element
in each mode will be described below.
[0075] The data memory 22a stores data signals in a rewritable
mode, in a manner similar to that of the memory 8a, and previously
stores frequency data corresponding to each country and an ID code
set to each receiver.
[0076] In power-on mode, the frequency switching controller 21a
reads the frequency data for weak read waves out of the data memory
22a and outputs it to the frequency controller 23a.
[0077] In normal operation mode, the frequency switching controller
21a reads frequency data corresponding to a frequency set signal
input by the frequency set signal decoder 25 out of the data memory
22a and outputs it to the frequency controller 23a.
[0078] In a power-on time, the data memory 22a outputs frequency
data for weak radio waves in response to a request from the
frequency switching controller 21a.
[0079] In a normal operation time, the data memory 22a frequency
data corresponding to a frequency set signal from among sets of
stored frequency data, in response to a request from the frequency
switching controller 21a.
[0080] In a power-on time, the frequency controller 23a controls
the frequency synthesizer 23b to lock on the oscillation frequency
of the frequency synthesizer 23b, based on the frequency data for
weak radio waves from the frequency switching controller 21a.
[0081] In a normal operation time, the frequency controller 23a
controls the frequency synthesizer 23b to lock on the oscillation
frequency of the frequency synthesizer 23b, based on the frequency
set data from the frequency switching controller 21a.
[0082] In a power-on time, the frequency synthesizer 23b outputs a
frequency signal for weak radio waves to the frequency converter
24b with the frequency locked on by the frequency controller
23a.
[0083] In a normal operation time, the frequency synthesizer 23b
outputs an oscillation frequency signal to the frequency converter
24b with the frequency locked on by the frequency controller
23a.
[0084] In a power-on time, the high frequency amplifier 24a
amplifies the frequency set signal received via the receiver
antenna 24d and outputs it to the frequency converter 24b.
[0085] In a normal operation time, the high frequency amplifier 24a
amplifies an operation signal received via the receiver antenna 24d
and outputs it to the frequency switching converter 24b.
[0086] In a power-on time, the frequency converter 24b converts
(mixes) the frequency set signal amplified by the high-frequency
amplifier 24a with the frequency signal for weak radio waves
oscillated by the frequency synthesizer 23b and outputs it to the
decoder 24c.
[0087] In a normal operation time, the frequency converter 24b
converts (mixes) the operation signal amplified by the
high-frequency amplifier 24a with the frequency signal oscillated
by the frequency synthesizer 23b and outputs it to the decoder
24c.
[0088] In a power-on time, the decoder circuit 24c decodes the
frequency set signal output from the frequency converter 24b and
outputs it to the frequency set signal decoder 25.
[0089] In a normal operation time, the decoder circuit 24c decodes
an operation signal output from the frequency converter 24b as a
servo drive signal to control each element of a radio controlled
model and then outputs it to the servo drive circuit in each
channel.
[0090] The frequency set signal decoder 25 operates in a power-on
mode. The frequency set signal decoder 25 decodes the frequency set
signal (containing ID information) input from the decoder circuit
24 and performs error decision and outputs a frequency set signal
matching all check items to the frequency switching controller
21a.
[0091] Next, an operation of the receiver will be described below
by referring to the flowchart in FIG. 3.
[0092] First, the receiver is powered on (S111).
[0093] Upon turning on the power source, the frequency data (second
frequency data) for weak radio waves stored in the data memory 22a
is read out. The oscillation frequency of the frequency synthesizer
23b is locked on based on the frequency data. The frequency
synthesizer 23b oscillates a frequency signal for weak radio waves
with the locked-on frequency and outputs it to the frequency
converter 24b (S112).
[0094] Then, the receiver waits the receiving of the frequency set
signal (frequency switching signal) carried with weak radio waves
of the second frequency (Si13). The receiving time of the frequency
switching signal has a lapse of a fixed period of time from the
turning on of the power source of the receiver, for example, a
receive waiting time of several tens seconds. The receiving
operation is ceased after a lapse of the waiting time.
[0095] When the frequency switching signal of weak radio waves is
received via the receiver antenna 24d (Yes in S113), the
high-frequency amplifier 24a amplifies the frequency switching
signal. The frequency converter 24b converts (mixes) the amplified
signal with the frequency signal for weak radio waves oscillated by
the frequency synthesizer 23b. The decoder circuit 24c decodes the
frequency switching signal. The ID code (or a device identification
code) for erroneous recognition prevention added to the frequency
switching signal) is subjected to data verification (S114). When
the data verification is matched (Yes in S114), the decoder circuit
24c decodes the frequency switching signal as a frequency set
signal. The data memory 22a sends out frequency data (first
frequency data) corresponding to the frequency set signal while it
stores the frequency data read out. The frequency synthesizer 23b
locks on its oscillation frequency based on the frequency set data
and outputs the frequency signal oscillated with the locked-on
frequency to the frequency converter 24b. Thus, the setting of the
receiving frequency (first frequency) has completed (S115).
[0096] The receiver includes further a LED (Light Emitting Diode).
When the receiver has completely set the frequency for reception
based on the frequency set signal (frequency switching signal) from
the transmitter, the LED blinks a predetermined number of
times.
[0097] When the data verification is failed (No in S114) or the
frequency switching signal by weak radio waves are not received (No
in S113), the receiver continues waiting until the frequency
switching signal of weak radio waves is received if the waiting
time is not over (No in S116).
[0098] When the frequency switching signal is not received during
the waiting time period (Yes in S116), the data memory 22a sends
out the previously used frequency data and outputs the frequency
signal oscillated based on the frequency data (as a receiving
frequency (first frequency)) to the frequency converter 24b. Thus,
the receiving operation begins.
[0099] After the frequency data to be transmitted and the frequency
data to be received are set, the following operation is
repeated.
[0100] The receiver antenna 24d receives an operation signal
transmitted from the transmitter. The high frequency amplifier 24a
amplifies the operation signal. The frequency converter 24b
converts (mixes) the amplified signal with the frequency signal
oscillated by the frequency synthesizer 23b. Thus, the decoder
circuit 24c decodes the converted signal as a servo drive signal
controlling each element in a radio controlled model and then
outputs it to the servo drive circuit in each channel (S117).
[0101] As described above, the radio control system for models
according to the present invention can select received frequencies,
with the receiver mounted in the radio control model. This feature
can eliminate the troublesome and time loss at the time of
switching the frequency.
[0102] Because a frequency switching signal at the start-up of the
power source is transmitted and received with weak radio waves, it
is preferable to perform the transmission and reception at, for
example, a close distance of about 3 m.
[0103] In the above embodiment, when the receiver has completely
set its receiving frequency based on the frequency set signal
(frequency switching signal) from the transmitter, the LED provided
on the receiver flashes a predetermined number of times to inform
the user of the completion of frequency setting. However, if the
same effect is obtained without limiting only to the embodiment, an
electronic buzzer, for example, may produce an electronic sound or
a drive signal may be transmitted only to a specific servo to
implement a specific operation. In this operation, the user can
ascertain more clearly that the received frequency has been
completely set in the receiver.
* * * * *