U.S. patent number 3,865,001 [Application Number 05/358,956] was granted by the patent office on 1975-02-11 for tempo enhancement device.
Invention is credited to Robert L. Hershey.
United States Patent |
3,865,001 |
Hershey |
February 11, 1975 |
Tempo enhancement device
Abstract
An electromechanical apparatus accompanies rhythmic human
movement with music of appropriate tempo. This is accomplished by
monitoring the activity with a transducer attached to a supporting
structure, which will move in response to shifts in human weight.
These peaks are counted and the measured count is used to control
the relative volumes of a multiplicity of differently paced musical
tracks.
Inventors: |
Hershey; Robert L. (Washington,
DC) |
Family
ID: |
26870251 |
Appl.
No.: |
05/358,956 |
Filed: |
May 10, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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174464 |
Aug 24, 1971 |
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Current U.S.
Class: |
84/723;
84/DIG.27; 84/741; 984/344; 84/DIG.1; 84/602; 984/347 |
Current CPC
Class: |
G10H
1/40 (20130101); G10H 1/32 (20130101); G10H
2220/341 (20130101); Y10S 84/01 (20130101); Y10S
84/27 (20130101) |
Current International
Class: |
G10H
1/40 (20060101); G10H 1/32 (20060101); G10h
003/00 () |
Field of
Search: |
;84/1.02,1.03,1.24,1.28,DIG.1,DIG.27,DIG.29 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wilkinson; Richard B.
Assistant Examiner: Witkowski; Stanley J.
Parent Case Text
This application is a continuation-in-part of application Ser. No.
174,464, filed Aug. 24, 1971, and now abaondoned.
Claims
What is claimed is:
1. In a device for changing the relative volumes of at least two
sources of differently paced musical selections in response to the
tempo of movement of a supporting structure caused by shifts of
human body weight;
a. an electromechanical transducer for sensing said structural
movement and producing a variable voltage in response thereto whose
peaks correspond to the excursions of the structure in response to
said shifts in human body weight;
b. an amplifier for amplifying said voltage;
c. a pulse shaper to form pulses from said amplified voltage;
d. a digital-to-analog network to produce from said pulses an
analog voltage proportional to their period of repetition;
e. a differential amplifier circuit to produce plural output
voltages from said analog voltage proportional to the period of
repetition;
f. a multichannel amplifier, a stage of amplification in each of
whose channels is biased by one of said output voltages, thus
producing differing levels of amplification;
g. at least two musical tracks having differing rhythm speeds,
prerecorded on different channels of a recording medium, which are
amplified to differing degrees by said multichannel amplifier;
and
h. at least two speakers to produce sound from said prerecorded
musical tracks.
Description
BACKGROUND OF THE INVENTION
This invention relates to an apparatus for automatically sensing
the tempo of some form of human activity and enchancing its rhythm
by actuating appropriately paced musical accompaniment.
In various situations it often is desirable to enhance the tempo of
some rhythmic activity such as dancing, gymnastics, trampoline
acrobatics, or exercising. Accompanying sound adds another
dimension to the activity, increasing the awareness of its rhythm
for the participants and spectators. Such accompaniment could
previously be obtained only through manual control of the music.
With this invention the control is automatic. By eliminating the
manual operator labor costs are saved, privacy is increased, and
the activity is more directly linked to its accompaniment.
SUMMARY OF THE INVENTION
Each type of rhythmic human activity generates some movement of the
supporting structure which can be instrumented by an appropriate
form of transducer, producing a time-varying voltage. The type of
activity dictates the most efficient transducer for monitoring.
Typical transducers that may be used in various embodiments of this
invention include accelerometers, spring-loaded contacts, strain
gauges, and conducting rubber rheostats. For instance in monitoring
dancing or gymnastics a vibrational transducer in contact with the
floor or mat such as an accelerometer could be used.
This invention comprises a unique electro-mechanical network which
responds to the repetition rate of the motion. This is transformed
into the repetition rate of a voltage through the use of a
transducer. The repetition rate of the motion is counted, and this
count is used to select the relative volume for each of a
multiplicity of differently paced music tracks.
An embodiment of the invention will now be described with reference
to the appended drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an external view of the apparatus, showing how it may be
used in conjunction with a home stereo tape recorder system.
FIG. 2 is a schematic diagram showing the electromechanical network
utilized in the embodiment.
FIG. 3 is a schematic diagram of the detail of the
digital-to-analog network.
FIG. 4 is a circuit diagram showing the detail of the differential
amplifier circuit.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIG. 1 the transducer 1, in this case an accelerometer is shown
monitoring an activity. The electrical signal from the transducer
is processed by the circuitry to be described, which is a
modification of a home stereo amplifier unit 2. The input to the
stereo amplifier consists of a home stereo tape recorder 3 playing
a special stereo tape 4, whose first channel consists of slow music
and whose second channel consists of appropriately syncopated fast
music. The stereo amplifier unit 2 sets the relative volume of the
music from the two tape tracks. A slow tempo in the monitored
activity causes the amplifier 2 to make the slow track louder
compared to the fast track. Similarly for a fast tempo activity the
sound of the faster musical background predominates. The music from
the two tracks, with their relative volumes thus regulated, issues
forth from the two speakers 5 and 6, respectively.
Referring to FIG. 2, the schematic of the electromechanical network
is shown. The signal produced by the transducer 1 is a time-varying
voltage with its peaks corresponding to the peaks of the movement
being monitored. These peaks occur when the shifting body weight
causes the supporting structure to make excursions above and below
its equilibrium position. The signal from the transducer is
amplified by a standard electronic amplifier circuit 8. This
amplified signal is input to the pulse shaper circuit 9, which
forms a pulse from each peak of the signal. These pulses control a
digital-to-analog network circuit 10 which generates an analog
voltage proportional to the time between pulses. The output of the
digital-to-analog network 10 forms the input to the differential
amplifier circuit 11. The left and right channels of a home stereo
amplifier constitute the slow and fast channels 12 and 13,
respectively. The differential amplifier circuit 11 uses this
voltage from the digital-to-analog network, proportional to the
period of pulse repetition to control the slow (left) channel
amplifier 12 and the fast (right) channel amplifier 13 of the home
stereo amplifier. This is done by biasing a stage of amplification
of each channel with voltage from differential amplifier, adjusting
the balance of volume between these two channels. If the voltage
from the digital-to-analog network 10 is equal to a preset level
corresponding to an intermediate speed pulse rate reference, the
sounds will be balanced in both channels. If the pulse rate is
higher than the preset level, the volume will be concentrated in
the fast channel; if less, it will be concentrated in the slow
channel. The right and left channels of the tape recorder output 14
and 15, which were derived from the special stereo tape 4, are then
amplified by the right and left channel amplifiers 12 and 13 of the
home stereo amplifier. Since the balance of the volume between
these amplifiers 12 and 13 has been adjusted on the basis of the
period of pulse repetition, the amplification of the fast track
channel will be greater if the pulse repetition rate is faster than
the reference rate and the amplification of the slow track channel
will be greater if the pulse repetition rate is slower than the
reference rate. The audio signals from the amplified musical tracks
then go the speakers 5 and 6. If the sensed motion is slow in tempo
then the sound from the slow channel speaker 5 will be louder and
predominate, and if the sensed motion is fast in tempo then the
sound from the fast channel speaker 6 will be louder and
predominate.
The detail of the digital-to-analog network is shown in FIG. 3. The
purpose of this network is to determine the time period between
successive pulses and put out an analog voltage proportional to
this period, and thus inversely proportional to the pulse
repetition rate. Incident pulses from the pulse shaper reset all
the elements of the digital-to-analog network and direct the set of
logic 19 to permit a train of pulses from the clock 18 to be
counted in the binary counter 20. When the next incident pulse
occurs, the contents of the binary counter are transferred to a
storage register where they are converted to analog form by the
digital-to-analog converter. Since the rate of the clock is known,
the time period between successive pulses can be determined by the
count accumulated by the counter during the period. The process of
counting can, therefore, continue for the next time interval, the
value of the count for the previous interval being stored in the
register. When the pulse occurs, the second counter number will be
read into the register 21, erasing the existing contents and
converting it to analog via the digital-to-analog converter 22. The
output of the digital-to-analog converter 22 is a voltage
proportional to the period. This voltage is then put through the
low pass filter 23 before being fed to the differential amplifier
circuit.
FIG. 4 shows the differential amplifier circuit consisting of a
subtractor amplifier and an inverter. The subtractor amplifier
portion consists of operational amplifier 24, associated resistors
25 and 26, dc bias voltage source 27, and potentiometer 28. The
inverter portion consists of operational amplifier 29 and
associated resistors 30 and 31. The filtered analog signal from the
digital-to-analog network is compared to the preset reference
voltage level of the potentiometer 28, which establishes the
balance position for the period of repetition. This reference
voltage corresponds to the voltage that would come from the
analog-to-digital network for an intermediate speed pulse
repetition rate. The subtractor amplifier produces a voltage
proportional to the difference between the reference voltage and
the analog input. This voltage determines the magnitude of voltage
biasing a stage of amplification of the fast channel of the stereo
amplifier and thus controls its gain. To obtain the algebraic
negative of the output voltage from the subtractor amplifier it is
fed to an inverter, consisting of operational amplifier 29 and
resistors 30 and 31. This results in a voltage equal to the
difference between the analog input and the reference voltage which
goes to the slow channel of the stereo amplifier. If the analog
input is larger in absolute value than the reference voltage, the
voltage to the fast channel amplifier will be negative and the
voltage to the slow channel amplifier will be positive. Both
voltages will be proportional to the difference between the analog
input and the reference. Conversely if the analog input is less
than the reference voltage the voltage to the fast channel
amplifier will be positive and the voltage to the slow channel
amplifier will be negative.
To obtain more than two speeds of background music additional
channels may be used with a device for selecting among the
channels. If enough additional channels are used an almost
continuous range of background music speeds can be obtained.
All that has been said with reference to a tape music reporduction
system could also be accomplished with a disc or some other form of
music reproduction system.
It is also possible to augment the sound with a light display of
various colors corresponding to various pulse repetition rates.
This can be accomplished by having bulbs of various colors light in
response to various levels of voltage measured at the output of the
low pass filter 23. One means of switching the bulbs is with a
control circuit such as described in U.S. Pat. No. 3,480,912 to S.
D. Speeth and P. C. Norem. Further rhythm accompaniment can be
obtained by triggering a rhythm instrument with the peak values of
the electrical signal from the transducer. Other modifications will
be obvious to those skilled in art.
The invention is not limited to the exemplary construction shown
above, but may be made in various ways within the scope of the
following claims.
* * * * *