US5095539A
Expired / Lapsed
US
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System and method of control tone amplitude modulation in a linked compression-expansion (Lincomplex) system
Assignee: Amaf Industries Inc
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Filing: 1990-08-20
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Granted: 1992-03-10
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Expires: 2010-08-20
Abstract
Abstract A linked compressor-expander (Lincompex) system and method varies the power of the control tone signal to maintain the power of the signal supplied to the transmitter substantially constant. The system measures a parameter related to the power level of the compressed information signal output from the compressor and varies the power of the control tone such that the sum of compressed information signal power and control tone power is substantially constant. When the input information signal drops below the compression range of the compressor, the control tone amplitude is thereby boosted to maintain the combined information signal and control tone signal power more nearly constant, and thus improve performance during low input information signal power levels. During these low input information signal power levels, the power of the control tone S/N is boosted so as to maintain higher control tone at the receive, thereby improving demodulator performance.
Inventors
- 👤 Howard Leveque
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 14:10
CPC Classifications
H; H03; H03G; H03G9/00; H03G9/005; H03G9/02; H03G9/12; H03G9/18
Claims Analysis
Total Claims: 44
Claim 1
Independent Claim
101 words
A method of preparing an input information signal for transmission over a communications channel comprising: (a) developing an envelope signal representative of the envelope of the input information signal; (b) compressing the input information signal in proportion to the level of said envelope signal within a compression range within which the compressed input information signal has a substantially constant output level; (c) developing a control tone signal having a control tone signal level from said envelope signal; (d) boosting the control tone signal level when the level of the compressed input information signal level falls below said substantially constant output level.
Claim 2
Independent Claim
101 words
A method of preparing an input information signal for transmission over a communications channel comprising: (a) developing an envelope signal representative of the envelope of the input information signal; (b) compressing the input information signal in proportion to the level of said envelope signal within a compression range within which the compressed input information signal has a substantially constant output level; (c) developing a control tone signal having a control tone signal level from said envelope signal; (d) boosting the control tone signal level when the level of the compressed input information signal level falls below said substantially constant output level.
Claim 3
Dependent Claim
29 words
The method of claim 1 further comprising summing the compressed input information and the control tone signal to produce a combined information signal for transmission over a communication channel.
Claim 4
Dependent Claim
39 words
The method of claim 1 further comprising: (e) sensing a parameter related t output level of said compressed input information signal, said step (d) of boosting occurring in response to said parameter monitored by said step (e) of sensing.
Claim 5
Dependent Claim
32 words
The method of claim 3 wherein said step (a) of developing includes detecting the envelope of the input information signal to produce an envelope signal; said monitored parameter being said envelope signal.
Claim 6
Dependent Claim
28 words
The method of claim 3 further comprising detecting the power of said compressed input information signal; said monitored parameter being the power of said compressed input information signal.
Claim 7
Dependent Claim
39 words
The method of claim 2 further comprising: (e) sensing a parameter related to output level of said compressed input information signal, said step (d) of boosting occurring in response to said parameter monitored by said step (e) of sensing.
Claim 8
Dependent Claim
26 words
The method of claim 6 further comprising detecting the power of said combined information signal; said monitored parameter being the power of said combined information signal.
Claim 9
Dependent Claim
59 words
The method of claim 1 wherein said information signal is any complex information signal, said compressed information signal having a predetermined frequency band, and said control tone signal having a predetermined control tone band; said method further comprising shifting the center frequency of at least one of said predetermined frequency band and control tone band to prevent overlap therebetween.
Claim 10
Dependent Claim
42 words
The method of claim 8 wherein said step of shifting is performed by frequency shifting the complex information signal to a different frequency so that all frequencies in said predetermined frequency band are separated from any frequencies within said control tone band.
Claim 11
Independent Claim
92 words
A method of preparing an information signal for transmission over a communication channel comprising the steps of: (a) generating a control tone having a power level and representing envelope information of the information waveform; (b) compressing the information waveform to produce a compressed signal having a power level by dividing the information waveform by the envelope of the information waveform; and (c) varying the power level of the control tone to produce n adjusted control tone in response to changes in a parameter related to the power level of the compressed signal.
Claim 12
Independent Claim
92 words
A method of preparing an information signal for transmission over a communication channel comprising the steps of: (a) generating a control tone having a power level and representing envelope information of the information waveform; (b) compressing the information waveform to produce a compressed signal having a power level by dividing the information waveform by the envelope of the information waveform; and (c) varying the power level of the control tone to produce n adjusted control tone in response to changes in a parameter related to the power level of the compressed signal.
Claim 13
Dependent Claim
28 words
The method as claimed in claim 10, further comprising the step of: (d) summing the compressed signal and adjusted control tone prior to transmission over a communication channel.
Claim 14
Dependent Claim
45 words
The method as claimed in claim 10, wherein said step (a) comprises the steps of: determining the envelope information of the information waveform; producing a logarithm signal of the envelope information; and frequency modulating a carrier using the logarithm signal to produce the control tone.
Claim 15
Dependent Claim
56 words
The method as claimed in claim 10, wherein said step (c) comprises the steps of: generating a control signal to control the power level of the control tone in accordance with the power level of the compressed signal; and varying an attenuation factor of the power level of the control tone according to the control signal.
Claim 16
Dependent Claim
15 words
The method as claimed in claim 10, wherein the information waveform is a voice signal.
Claim 17
Dependent Claim
16 words
The method s claimed in claim 10, wherein the information waveform is a complex data signal.
Claim 18
Independent Claim
62 words
A method of preparing an information signal for transmission over a communication channel comprising: (a) inputting an information signal; (b) generating a Lincompex signal having a compressed signal and a control tone representing the information signal, each having a power level; and (c) varying the power level of the control tone to maintain the combined output signal at a constant power level.
Claim 19
Independent Claim
62 words
A method of preparing an information signal for transmission over a communication channel comprising: (a) inputting an information signal; (b) generating a Lincompex signal having a compressed signal and a control tone representing the information signal, each having a power level; and (c) varying the power level of the control tone to maintain the combined output signal at a constant power level.
Claim 20
Dependent Claim
47 words
The method as claimed in claim 16, wherein said step (b) comprises the steps of: determining the envelope of the information signal; producing a logarithm signal representative of the logarithm of the envelope; and frequency modulating a carrier using the logarithm signal to produce the control tone.
Claim 21
Dependent Claim
62 words
The method as claimed in claim 23, wherein said step (c) comprises the steps of: (e) generating a control signal to control the power level of the control tone in accordance with a parameter relative to the power level of the compressed signal; and (f) varying an attenuation factor of the power level of the control tone according to the control signal.
Claim 22
Independent Claim
120 words
A system for preparing an input information signal for transmission over a communications channel comprising: an envelope detector developing an envelope signal representative of the envelope of the input information signal; a compressor compressing the input information signal in proportion to the level of said envelope signal within a compression range within which the compressed input information signal has a substantially constant output level; means, responsive to said envelope detector, for developing a control tone signal having a control tone signal level from said envelope signal; control tone modulation means for boosting the control tone signal level received from said means for developing when the level of the compressed input information signal level falls below said substantially constant output level.
Claim 23
Independent Claim
120 words
A system for preparing an input information signal for transmission over a communications channel comprising: an envelope detector developing an envelope signal representative of the envelope of the input information signal; a compressor compressing the input information signal in proportion to the level of said envelope signal within a compression range within which the compressed input information signal has a substantially constant output level; means, responsive to said envelope detector, for developing a control tone signal having a control tone signal level from said envelope signal; control tone modulation means for boosting the control tone signal level received from said means for developing when the level of the compressed input information signal level falls below said substantially constant output level.
Claim 24
Dependent Claim
31 words
The system of claim 19 further comprising a summer summing the compressed input information and the control tone signal to produce a combined information signal for transmission over a communication channel.
Claim 25
Dependent Claim
39 words
The system of claim 19 further comprising: means for measuring a parameter related to output level of said compressed input information signal, said control tone modulation means boosting the control tone signal level in response to said measured parameter.
Claim 26
Dependent Claim
21 words
The system of claim 21 wherein said envelope detector is said means for measuring, said measured parameter being said envelope signal.
Claim 27
Dependent Claim
35 words
The system of claim 21 wherein said means for measuring comprises a power detector detecting the power of said compressed input information signal; said measured parameter being the power of said compressed input information signal.
Claim 28
Dependent Claim
39 words
The system of claim 20 further comprising: means for measuring a parameter related to output level of said compressed input information signal, said control tone modulation means boosting the control tone signal level in response to said measured parameter.
Claim 29
Dependent Claim
33 words
The system of claim 24 wherein said means for measuring comprises a power detector detecting the power of said combined information signal; said measured parameter being the power of said combined information signal.
Claim 30
Dependent Claim
62 words
The system of claim 19 wherein said information signal is any complex information signal, said compressed information signal having a predetermined frequency band, and said control tone signal having a predetermined control tone band; said system further comprising mixer means for shifting the center frequency of at least one of said predetermined frequency band and control tone band to prevent overlap therebetween.
Claim 31
Dependent Claim
38 words
The system of claim 26 wherein said mixer means frequency shifts the complex information signal to a different frequency so that all frequencies in said predetermined frequency band are separated from any frequencies within said control tone band.
Claim 32
Independent Claim
108 words
A system for preparing information signal for transmission over a communication channel comprising: control tone generating means for generating a control tone representing envelope information of said information signal, said control tone having a power level; compressing means, responsive to said control tone generating means, for compressing said information signal into a compressed signal by dividing said information waveform by said envelope of said information signal said compressed signal having a power level; and power compensation means for varying the power level of said control tone to produce an adjusted control tone in response to changes in a parameter related to the power level of said compressed signal.
Claim 33
Independent Claim
108 words
A system for preparing information signal for transmission over a communication channel comprising: control tone generating means for generating a control tone representing envelope information of said information signal, said control tone having a power level; compressing means, responsive to said control tone generating means, for compressing said information signal into a compressed signal by dividing said information waveform by said envelope of said information signal said compressed signal having a power level; and power compensation means for varying the power level of said control tone to produce an adjusted control tone in response to changes in a parameter related to the power level of said compressed signal.
Claim 34
Dependent Claim
38 words
The system as claimed in claim 28, wherein said transmitting means comprises: summing means, operatively connected to said compressing means and said power compensation means, for summing said compressed signal and said adjusted control tone prior to transmission.
Claim 35
Dependent Claim
79 words
The system as claimed in claim 28, wherein said control tone generating means comprises: envelope detecting means, operatively connected to said input means, for determining said envelope information of said information signal; log amplifier means, operatively connected to said envelope detecting means, for producing a logarithm signal representative of the logarithm of said envelope information; and modulation means, operatively connected to said log amplifier means, for frequency modulating a carrier with said logarithm signal to produce said control tone.
Claim 36
Dependent Claim
85 words
The system as claimed in claim 28, wherein said power compensating means comprises: control tone power control means, operatively connected to said compressing means, for generating a control signal to control the power level of said control tone in accordance with the power level of said compressed signal; and power attenuation means, operatively connected to said control tone generating means and said control tone power control means, for varying an attenuation factor of the power level of said control tone according to said control signal.
Claim 37
Dependent Claim
113 words
The system as claimed in claim 29, wherein said power compensating means comprises: power detecting means, operatively connected to said summing means, for measuring power of the summed signal; control tone power control means, operatively connected to said power detecting means, for generating a control signal to control the power level of said control tone according to the power level of said summed signal such that the power of said summed signal is maintained at a relatively constant level; and power attenuation means, operatively connected to said control tone power control means and said control tone generating means, for variably attenuating the power level of said control tone according to said control signal.
Claim 38
Dependent Claim
14 words
The system claimed in claim 28, wherein said information signal is a voice signal.
Claim 39
Dependent Claim
16 words
The system as claimed in claim 28, wherein said information signal is a complex data signal.
Claim 40
Independent Claim
76 words
A system for preparing an information signal for transmission over a communication channel comprising: input means for inputting an information waveform; modulating means, operatively connected to said input means, for producing an output signal including a compressed signal and a control tone, each having a power level; and power compensation means, operatively connected to said modulating means, for varying the power level of said control tone to maintain said output signal at a constant power level.
Claim 41
Independent Claim
76 words
A system for preparing an information signal for transmission over a communication channel comprising: input means for inputting an information waveform; modulating means, operatively connected to said input means, for producing an output signal including a compressed signal and a control tone, each having a power level; and power compensation means, operatively connected to said modulating means, for varying the power level of said control tone to maintain said output signal at a constant power level.
Claim 42
Dependent Claim
73 words
The system as claimed in claim 35, wherein said Lincompex modulating means comprises: envelope detecting means, operatively connected to said input means, for determining envelope information of said information signal; log amplifier means, operatively connected to said envelope detecting means, for producing a logarithm signal representative of the envelope; and modulation means, operatively connected to said log amplifier means, for frequency modulating a carrier with said logarithm signal to produce said control tone.
Claim 43
Dependent Claim
84 words
The system as claimed in claim 35, wherein said power compensating means comprises: control tone power control means, operatively connected to said modulating means, for generating a control signal to control the power level of said control tone in accordance with a parameter related to the power level of said compressed signal; and power attenuation means, operatively connected to said modulating mens and said control tone power control means, for variably attenuation the power level of said control tone according to said control signal.
Claim 44
Dependent Claim
104 words
The system as claimed in claim 35, wherein said power compensating means comprises: power detecting means, operatively connected to said Lincompex modulating means, for measuring a power of the signal; control tone power control means, operatively connected to said Lincompex modulating means and said power detecting means, for generating a control signal to control the power level of said control tone to maintain the power level of said signal relatively constant; and power attenuation means, operatively connected to said control tone power control means and said Lincompex modulating means, for variably attenuation the power level of said control tone according to said control signal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-03-10 | 1995-09-09 | 1996-03-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-03-10 | 1999-09-09 | 2000-03-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-03-10 | 2003-09-09 | 2004-03-10 | $7700.00 | Window Closed / Lapsed |