Patent US3644657A successfully refreshed from Google Patents.
US3644657A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic audiofrequency modulation system and method
Assignee: Individual
•
Filing: 1969-10-20
•
Granted: 1972-02-22
•
Expires: 1989-10-20
Abstract
Abstract The invention is directed to modulation of the amplitude and frequency of an audiofrequency signal by passing the signal through at least two parallel channels, with phase-shifting circuitry in the channels providing signals of opposed phases. A low-frequency band is filtered from the signal in one of the channels and a high-frequency band is filtered from the signal in another of the channels and the signals shifted back into phase. The filtered signals are then combined into an output signal. The high- and low-frequency bands filtered from the signals are selectively varied to induce vibrato, tremolo, and other tonal effects into the output signal. In a preferred form of the invention, the high- and low-pass filters are matched so as to form substantially a 180* phase shift stage with a flat frequency response. Four stages are coupled to provide 720* of phase shift. The original audiofrequency signal is then summed with the phaseshifted signal in approximately equal proportions to produce a coordinated effect substantially duplicating that produced by a rotating speaker. The phase shift is started and stopped in a manner to duplicate the dynamic effects of starting and stopping a rotating speaker. A dual channel system is described for duplicating a multiple speaker system.
Inventors
- 👤 Francis A Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 19:51
CPC Classifications
G; G10; G10H; G10H1/00; G10H1/02; G10H1/04
Claims Analysis
Total Claims: 50
Claim 1
Independent Claim
67 words
A system for modulating a signal comprising: a. a plurality of parallel-connected filter means each discriminating against different frequencies, b. means for applying electrical signals representative of said signal with different phases to said filter means, c. means for varying the frequency response of at least one of said filter means, and d. means for recombining the outputs of said filter means with the signal being modulated.
Claim 2
Independent Claim
67 words
A system for modulating a signal comprising: a. a plurality of parallel-connected filter means each discriminating against different frequencies, b. means for applying electrical signals representative of said signal with different phases to said filter means, c. means for varying the frequency response of at least one of said filter means, and d. means for recombining the outputs of said filter means with the signal being modulated.
Claim 3
Dependent Claim
31 words
The system of claim 1 wherein one of said filter means discriminates against frequencies below a preselected frequency and another of said filter means discriminates against frequencies above said preselected frequency.
Claim 4
Dependent Claim
30 words
The system of claim 2 wherein the electrical signal applied to said one filter means is 180* out of phase with the electrical signal applied to said another filter means.
Claim 5
Dependent Claim
29 words
The system of claim 1 wherein the frequency response of a pair of said filter means is varied to modulate both the frequency and the amplitude of said signal.
Claim 6
Dependent Claim
121 words
A modulation system for audiofrequency signals comprising: a. first filter means for discriminating against frequencies below a first rollover audiofrequency, b. second filter means connected in parallel with said first filter means and discriminating against frequencies above a second rollover audiofrequency such that the cutoff frequency responses of said first and second filter means overlap at a crossover frequency, c. means for applying audiofrequency signals to said first and second filter means in phase opposition, d. means for cyclically varying said crossover frequency by increasing the rollover frequency of one of said filter means while concurrently decreasing the rollover frequency of the other of said filter means, and e. means for comBining the outputs of said first and second filter means.
Claim 7
Dependent Claim
121 words
A modulation system for audiofrequency signals comprising: a. first filter means for discriminating against frequencies below a first rollover audiofrequency, b. second filter means connected in parallel with said first filter means and discriminating against frequencies above a second rollover audiofrequency such that the cutoff frequency responses of said first and second filter means overlap at a crossover frequency, c. means for applying audiofrequency signals to said first and second filter means in phase opposition, d. means for cyclically varying said crossover frequency by increasing the rollover frequency of one of said filter means while concurrently decreasing the rollover frequency of the other of said filter means, and e. means for comBining the outputs of said first and second filter means.
Claim 8
Dependent Claim
29 words
The system of claim 5 and further comprising means for selectively varying the frequency of the cyclical variations in the frequency response of said first and second filter means.
Claim 9
Dependent Claim
34 words
The system of claim 5 wherein each said filter means comprises: a series connected capacitor and resistor tuned to discriminate against preselected frequency bands, said resistor being variable to change the preselected frequency bands.
Claim 10
Independent Claim
100 words
A system for modulating the audiofrequency output signal of a musical instrument comprising: a. a first filter network for discriminating against low frequencies connected to receive said output signal, b. a second filter network for discriminating against high frequencies connected in parallel to said first filter network, c. first and second modulation networks each connected to one of said filter networks, each modulation network including parallel high and low bandpass filters for operating on signals of opposed phases, d. means for varying the frequency responses of said modulation networks, and e. means for combining the outputs of said modulation networks.
Claim 11
Independent Claim
100 words
A system for modulating the audiofrequency output signal of a musical instrument comprising: a. a first filter network for discriminating against low frequencies connected to receive said output signal, b. a second filter network for discriminating against high frequencies connected in parallel to said first filter network, c. first and second modulation networks each connected to one of said filter networks, each modulation network including parallel high and low bandpass filters for operating on signals of opposed phases, d. means for varying the frequency responses of said modulation networks, and e. means for combining the outputs of said modulation networks.
Claim 12
Dependent Claim
117 words
The system of claim 8 wherein each of said modulation networks includes a tremulant circuit comprising: a. means for generating two signals in phase opposition each representative of said audiofrequency output signal, b. first filter means for discriminating against frequencies below a first rollover frequency connected to receive one of said two signals, c. second filter means connected in parallel with said first filter means for receiving the other of said two signals and for discriminating against frequencies above a second rollover frequency so that the cutoff frequency responses of said filter means overlap at a crossover frequency, said d. means for varying the magnitude of said crossover frequency by variance of elements in said filter means.
Claim 13
Dependent Claim
33 words
The system of claim 9 wherein said first modulation network comprises four of said tremulant circuits connected in series and said second modulation network comprises three of said tremulant circuits connected in series.
Claim 14
Independent Claim
57 words
The method of modulating an electrical signal comprising: a. filtering different frequency bands from a plurality of parallel phase-shifted signals each representative of said electrical signal, b. varying the frequency bands filtered from said phase-shifted signals, c. combining the filter signals, and d. varying the rate of variance of the frequency bands filtered from said phase-shifted signals.
Claim 15
Independent Claim
57 words
The method of modulating an electrical signal comprising: a. filtering different frequency bands from a plurality of parallel phase-shifted signals each representative of said electrical signal, b. varying the frequency bands filtered from said phase-shifted signals, c. combining the filter signals, and d. varying the rate of variance of the frequency bands filtered from said phase-shifted signals.
Claim 16
Dependent Claim
14 words
The method of claim 11 wherein said phase-shifted signals are 180* out of phase.
Claim 17
Dependent Claim
37 words
The method of claim 11 and further comprising: a. filtering frequencies above a selected first frequency from one of said phase-shifted signals, and b. filtering frequencies below a selected second frequency from another of said phase-shifted signals.
Claim 18
Independent Claim
69 words
The method of imparting tremulant effects into an audiofrequency output from a musical instrument comprising: a. generating a pair of parallel phase-shifted electrical signals each representative of said output, b. filtering frequencies above a preselected reference frequency from one of said electrical signals, c. filtering frequencies below said reference frequency from the other of said electrical signals, d. combining the filtered electrical signals, and e. varying said reference frequency.
Claim 19
Independent Claim
69 words
The method of imparting tremulant effects into an audiofrequency output from a musical instrument comprising: a. generating a pair of parallel phase-shifted electrical signals each representative of said output, b. filtering frequencies above a preselected reference frequency from one of said electrical signals, c. filtering frequencies below said reference frequency from the other of said electrical signals, d. combining the filtered electrical signals, and e. varying said reference frequency.
Claim 20
Dependent Claim
17 words
The method of claim 14 wherein the phases of said electrical signals are 180* out of phase.
Claim 21
Dependent Claim
20 words
The method of claim 14 wherein the cutoff frequency responses of said filtered electrical signals overlap at a crossover frequency.
Claim 22
Dependent Claim
21 words
The method of claim 16 wherein said crossover frequency occurs at the 50-percent level of each of said cutoff frequency responses.
Claim 23
Dependent Claim
92 words
In a tremulant system for musical sound the combination of: first means for producing a first electrical signal representative of sound produced by a musical instrument, second means for cyclically shifting the phase of said first electrical signal to produce a second electrical signal in which the phase angle is cyclically varied relative to the first electrical signal by an angle greater than about 540*, and third means for summing said first electrical signal and said second electrical signal to produce a third electrical signal that is both frequency and amplitude modulated.
Claim 24
Dependent Claim
92 words
In a tremulant system for musical sound the combination of: first means for producing a first electrical signal representative of sound produced by a musical instrument, second means for cyclically shifting the phase of said first electrical signal to produce a second electrical signal in which the phase angle is cyclically varied relative to the first electrical signal by an angle greater than about 540*, and third means for summing said first electrical signal and said second electrical signal to produce a third electrical signal that is both frequency and amplitude modulated.
Claim 25
Dependent Claim
23 words
The system of claim 18 wherein the first and second signals are summed in a ratio ranging from about 1:2 to about 2:1.
Claim 26
Dependent Claim
29 words
The system of claim 18 wherein the phase of the first electrical signal is shifted through an angle approximately equal to 2 pi n, where n is an integer.
Claim 27
Dependent Claim
22 words
The combination defined in claim 18 further characterized by: fourth means for producing audible sounds in response to the third electrical signal.
Claim 28
Dependent Claim
14 words
The combination defined in claim 21 wherein the first means includes a musical instrument.
Claim 29
Dependent Claim
51 words
The combination of claim 18 wherein the second means includes means for selectively shifting the phase of the first electrical signal at a first cyclical rate of from about 3 to about 10 cycles per second, and at a second cyclical rate of from 0 to about 3 cycles per second.
Claim 30
Dependent Claim
37 words
The combination defined in claim 23 wherein the second means further includes means for changing from one cyclic rate to the other cyclic rate in a predetermined manner to stimulate the inertial characteristics of a rotating speaker.
Claim 31
Dependent Claim
49 words
The combination defined in claim 18 wherein the second means includes: means for cyclically shifting the phase of said first electrical signal at a vibrato rate, and means for iniating the cyclic phase shift by progressively increasing the cyclical rate to stimulate the inertial characteristics of a rotating speaker.
Claim 32
Dependent Claim
49 words
The combination defined in claim 18 wherein the second means includes: means for cyclically shifting the phase of said first electrical signal at a vibrato rate, and means for terminating the cyclic phase shift by progressively decreasing the cycle rate to stimulate the inertial characteristics of a rotating speaker.
Claim 33
Dependent Claim
55 words
The tremulant system comprising means for producing a sound from a stationary speaker that is tremulated at a rate such as to simulate the sound produced by a speaker rotating at said rate, said means including means for progressively initiating and progressively terminating the tremulant rate to simulate the inertial characteristics of the rotating speaker.
Claim 34
Dependent Claim
55 words
The tremulant system comprising means for producing a sound from a stationary speaker that is tremulated at a rate such as to simulate the sound produced by a speaker rotating at said rate, said means including means for progressively initiating and progressively terminating the tremulant rate to simulate the inertial characteristics of the rotating speaker.
Claim 35
Independent Claim
86 words
The method for producing a musical sound from a fixed speaker approximating that produced by a rotating speaker which comprises cyclically shifting the phase of a first signal representative of the musical sound at a rate corresponding to the rate of rotation of the speaker, said phase being shifted through a phase angle in excess of about 540* to produce a second signal, and summing the first signal and the second signal to produce a third signal representative of musical sound produced by a rotating speaker.
Claim 36
Independent Claim
86 words
The method for producing a musical sound from a fixed speaker approximating that produced by a rotating speaker which comprises cyclically shifting the phase of a first signal representative of the musical sound at a rate corresponding to the rate of rotation of the speaker, said phase being shifted through a phase angle in excess of about 540* to produce a second signal, and summing the first signal and the second signal to produce a third signal representative of musical sound produced by a rotating speaker.
Claim 37
Dependent Claim
22 words
The method of claim 28 wherein the first and second signals are summed in a ratio between about 2:1 and about 1:2.
Claim 38
Dependent Claim
29 words
The method of claim 29 wherein the phase of the first signal is shifted through a phase angle of about phi 2 pi n where n is an integer.
Claim 39
Dependent Claim
151 words
The tremulant system for producing musical sound comprising: variable phase shift means for shifting the relative phase of first and second signals each representative of the same musical sound, the variable phase shift means comprising a plurality of variable phase shift stages, each stage comprising a transistor, a biasing network for the transistor, a capacitor connecting the collector of the transistors to the output of the stage, and a variable resistance connecting the emitter of the transistor To the output, the variable resistance of each stage being varied by said means for cyclically varying the degree of phase shift of the phase shift means, means for cyclically varying the phase shift means so as to vary the degree of relative phase shift from a minimum value to a maximum value at a selected vibrato rate, and a summation network for summing the first and second signals to produce a tremulant signal.
Claim 40
Dependent Claim
151 words
The tremulant system for producing musical sound comprising: variable phase shift means for shifting the relative phase of first and second signals each representative of the same musical sound, the variable phase shift means comprising a plurality of variable phase shift stages, each stage comprising a transistor, a biasing network for the transistor, a capacitor connecting the collector of the transistors to the output of the stage, and a variable resistance connecting the emitter of the transistor To the output, the variable resistance of each stage being varied by said means for cyclically varying the degree of phase shift of the phase shift means, means for cyclically varying the phase shift means so as to vary the degree of relative phase shift from a minimum value to a maximum value at a selected vibrato rate, and a summation network for summing the first and second signals to produce a tremulant signal.
Claim 41
Dependent Claim
40 words
The tremulant system of claim 31 wherein at least one of the stages includes means for selectively limiting the maximum and minimum values of the variable resistance to adjust the total cyclic phase shift produced by the phase shift means.
Claim 42
Dependent Claim
103 words
The tremulant system for producing musical sound comprising: variable phase shift means for shifting the relative phases of first and second signals, each representative of the same musical sound, means for cyclically varying the phase shift means so as to vary the degree of relative phase shift from a minimum value to a maximum value at a selected vibrato rate, a summation network for summing the first and second signals to produce a tremulant signal, and phase shift means for selectively varying the relative phase of the first and second signals at the extremes of phase shift produced by the phase shift means.
Claim 43
Dependent Claim
103 words
The tremulant system for producing musical sound comprising: variable phase shift means for shifting the relative phases of first and second signals, each representative of the same musical sound, means for cyclically varying the phase shift means so as to vary the degree of relative phase shift from a minimum value to a maximum value at a selected vibrato rate, a summation network for summing the first and second signals to produce a tremulant signal, and phase shift means for selectively varying the relative phase of the first and second signals at the extremes of phase shift produced by the phase shift means.
Claim 44
Dependent Claim
84 words
The tremulant system for producing musical sound comprising: variable phase shift means for shifting the relative phase of first and second signals each representative of the same musical sound, means for cyclically varying the phase shift means so as to vary the degree of relative phase shift from a minimum value to a maximum value greater than the minimum value by about 540* at a selected vibrato rate, and a summation network for summing the first and second signals to produce a tremulant signal.
Claim 45
Dependent Claim
84 words
The tremulant system for producing musical sound comprising: variable phase shift means for shifting the relative phase of first and second signals each representative of the same musical sound, means for cyclically varying the phase shift means so as to vary the degree of relative phase shift from a minimum value to a maximum value greater than the minimum value by about 540* at a selected vibrato rate, and a summation network for summing the first and second signals to produce a tremulant signal.
Claim 46
Dependent Claim
128 words
The tremulant system for producing musical sound comprising: first and second circuits each comprising variable phase shift means for shifting the relative phase of first and second signals each representative of the same musical sound, means for cyclically varying the phase shift means so as to vary the degree of relative phase shift from a minimum value to a maximum value at a selected vibrato rate, a summation network for summing the first and second signals to produce a tremulant signal, high pass filter means in the first circuit for excluding a low frequency range, low pass filter means in the second circuit for excluding a high frequency range, and wherein the phase shift means in the first and second circuits are cyclically varied at different vibrato rates.
Claim 47
Dependent Claim
128 words
The tremulant system for producing musical sound comprising: first and second circuits each comprising variable phase shift means for shifting the relative phase of first and second signals each representative of the same musical sound, means for cyclically varying the phase shift means so as to vary the degree of relative phase shift from a minimum value to a maximum value at a selected vibrato rate, a summation network for summing the first and second signals to produce a tremulant signal, high pass filter means in the first circuit for excluding a low frequency range, low pass filter means in the second circuit for excluding a high frequency range, and wherein the phase shift means in the first and second circuits are cyclically varied at different vibrato rates.
Claim 48
Dependent Claim
40 words
The tremulant system of claim 36 wherein the phase shift means in the first circuit produces a relative phase shift of about 720*, and the phase shift means in the second circuit produces a relative phase shift of about 540*.
Claim 49
Dependent Claim
86 words
The tremulant system for producing musical sound comprising: variable phase shift means for shifting the relative phase of first and second signals each representative of the same musical sound, means for cyclically varying the phase shift means so as to vary the degree of relative phase shift from a minimum value to a maximum value at a selected vibrato rate, and a summation network for summing the first and second signals in an amplitude ratio from about 2:1 to about 1:2 to produce a tremulant signal.
Claim 50
Dependent Claim
86 words
The tremulant system for producing musical sound comprising: variable phase shift means for shifting the relative phase of first and second signals each representative of the same musical sound, means for cyclically varying the phase shift means so as to vary the degree of relative phase shift from a minimum value to a maximum value at a selected vibrato rate, and a summation network for summing the first and second signals in an amplitude ratio from about 2:1 to about 1:2 to produce a tremulant signal.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-02-21 | 1975-08-23 | 1976-02-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-21 | 1979-08-23 | 1980-02-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-21 | 1983-08-23 | 1984-02-22 | $7700.00 | Window Closed / Lapsed |