Patent US4079330A successfully refreshed from Google Patents.
US4079330A
Expired / Lapsed
US
⏱️ 0.0 years remaining
System for demodulating angle-modulated signals
Assignee: Victor Company of Japan Ltd
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Filing: 1976-12-01
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Granted: 1978-03-14
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Expires: 1996-12-01
Abstract
Abstract The inventive system demodulates angle-modulated signals. A tracking band-pass filter responds to an input angle-modulated wave signal. The tracking filter has a pass band with a center frequency controlled by a control signal. A first amplitude limiter limits the amplitude of the input angle-modulated wave signal. A differentiation circuit establishes a 90° phase difference between a signal passing through the tracking band-pass filter and a signal passing through the amplitude limiter. A phase comparator responds to an input with the two signals with a 90° phase difference therebetween and produces an output error signal in accordance with this phase difference. This output error signal is supplied as the control signal to the tracking band-pass filter. This output error signal is also passed through a low pass filter to produce the demodulated signal.
Inventors
- 👤 Yukinobu Ishigaki
- 👤 Kohei Sasamura
- 👤 Yasuo Itoh
- 👤 Teruo Muraoka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 02:56
CPC Classifications
H; H04; H04H; H04H20/00; H04H20/86; H04H20/88; H03; H03D; H03D3/00; H03D3/001; H03D3/003; H03D3/005; H03D3/02; H03D3/06; H03D3/24; H03D3/26; H04H20/89
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
166 words
A system for demodulating angle-modulated wave signals comprising: a first phase shifting circuit supplied with an angle-modulated signal; first amplitude limiting means for limiting the amplitude of an output signal of said first phase shifting circuit; a second phase shifting circuit supplied with the angle-modulated signal, said first and second phase shifting circuits producing outputs having a relative phase differece of 90°; tracking band-pass filtering means responsive to the output signal of the second phase shifting circuit and having a pass band with a center frequency which is controlled by a control signal; second amplitude means for limiting the amplitude of the output signal of said tracking band-pass filtering means; phase comparing means responsive to the output signals of said first and second amplitude limiting means for producing an error signal in accordance with the phase difference between said output signals; means responsive to said error signal for controlling said tracking band-pass filtering means; and means responsive to said error signal for deriving a demodulated signal.
Claim 2
Independent Claim
166 words
A system for demodulating angle-modulated wave signals comprising: a first phase shifting circuit supplied with an angle-modulated signal; first amplitude limiting means for limiting the amplitude of an output signal of said first phase shifting circuit; a second phase shifting circuit supplied with the angle-modulated signal, said first and second phase shifting circuits producing outputs having a relative phase differece of 90°; tracking band-pass filtering means responsive to the output signal of the second phase shifting circuit and having a pass band with a center frequency which is controlled by a control signal; second amplitude means for limiting the amplitude of the output signal of said tracking band-pass filtering means; phase comparing means responsive to the output signals of said first and second amplitude limiting means for producing an error signal in accordance with the phase difference between said output signals; means responsive to said error signal for controlling said tracking band-pass filtering means; and means responsive to said error signal for deriving a demodulated signal.
Claim 3
Independent Claim
174 words
A system for demodulating angle-modulated signals comprising: tracking band-pass filtering means supplied with an angle-modulated input signal, said filter means having a pass band with a center frequency which is variably controlled responsive to a control signal; first amplitude limiting means for limiting the amplitude of the angle-modulated input signal; phase-shifting means for establishing a phase difference of 90° between a signal passing through said tracking band-pass filtering means and a signal passing through said amplitude limiting means; phase comparing means responsive to the 90° phase difference signals for producing an output error signal in accordance with said phase difference; amplitude expansion means in a signal transmission system including a first amplitude limiting means, means whereby said amplitude expansion means lowers the level of the angle-modulated signals supplied to the phase comparing means responsive to levels of the input angle-modulated signals which are below a predetermined level; means responsive to said output error signal for controlling said tracking band-pass filtering means; and means responsive to said output error signal for deriving a demodulating signal.
Claim 4
Independent Claim
174 words
A system for demodulating angle-modulated signals comprising: tracking band-pass filtering means supplied with an angle-modulated input signal, said filter means having a pass band with a center frequency which is variably controlled responsive to a control signal; first amplitude limiting means for limiting the amplitude of the angle-modulated input signal; phase-shifting means for establishing a phase difference of 90° between a signal passing through said tracking band-pass filtering means and a signal passing through said amplitude limiting means; phase comparing means responsive to the 90° phase difference signals for producing an output error signal in accordance with said phase difference; amplitude expansion means in a signal transmission system including a first amplitude limiting means, means whereby said amplitude expansion means lowers the level of the angle-modulated signals supplied to the phase comparing means responsive to levels of the input angle-modulated signals which are below a predetermined level; means responsive to said output error signal for controlling said tracking band-pass filtering means; and means responsive to said output error signal for deriving a demodulating signal.
Claim 5
Independent Claim
233 words
A system for demodulating angle-modulated signals comprising: tracking band-pass filtering means supplied with an angle-modulated input signal, said filter means having a pass band with a center frequency which is variably controlled responsive to a control signal; first amplitude limiting means for limiting the amplitude of the angle-modulated input signal; phase-shifting means for establishing a phase difference of 90° between a signal passing through said tracking band-pass filtering means and a signal passing through said amplitude limiting means; phase comparing means responsive to the 90° phase difference signals for producing an output error signal in accordance with said phase difference; means responsive to said output error signal for controlling said tracking band-pass filtering means; envelope detecting means for generating a control signal responsive to a detection of the envelope of the input angle-modulated signal; loop gain controlling means for controlling the level of the output signal of the phase comparing means responsive to the control signal of the envelope detecting means; means for supplying the output of said loop gain controlling means to the tracking band-pass filtering means as the control signal; and means responsive to said output error signal for deriving a demodulated signal, said demodulated signal driving means including operation circuit means responsive to the output signal of the phase comparing means and the output signal of the loop gain controlling means for producing an output signal having a constant level.
Claim 6
Independent Claim
233 words
A system for demodulating angle-modulated signals comprising: tracking band-pass filtering means supplied with an angle-modulated input signal, said filter means having a pass band with a center frequency which is variably controlled responsive to a control signal; first amplitude limiting means for limiting the amplitude of the angle-modulated input signal; phase-shifting means for establishing a phase difference of 90° between a signal passing through said tracking band-pass filtering means and a signal passing through said amplitude limiting means; phase comparing means responsive to the 90° phase difference signals for producing an output error signal in accordance with said phase difference; means responsive to said output error signal for controlling said tracking band-pass filtering means; envelope detecting means for generating a control signal responsive to a detection of the envelope of the input angle-modulated signal; loop gain controlling means for controlling the level of the output signal of the phase comparing means responsive to the control signal of the envelope detecting means; means for supplying the output of said loop gain controlling means to the tracking band-pass filtering means as the control signal; and means responsive to said output error signal for deriving a demodulated signal, said demodulated signal driving means including operation circuit means responsive to the output signal of the phase comparing means and the output signal of the loop gain controlling means for producing an output signal having a constant level.
Claim 7
Independent Claim
175 words
A system for demodulating angle-modulated signals comprising: tracking band-pass filtering means supplied with an angle-modulated input signal, said filter means having a pass band with a center frequency which is variably controlled responsive to a control signal; first amplitude limiting means for limiting the amplitude of the angle-modulated input signal; phase-shifting means for establishing a phase difference of 90° between a signal passing through said tracking band-pass filtering means and a signal passing through said amplitude limiting means; first phase comparing means responsive to the 90° phase difference signals for producing an output error signal in accordance with said phase difference; means responsive to said output error signal for controlling said tracking band-pass filtering means; second phase comparing means for comparing the phase of the input angle-modulated signal to be supplied to the tracking band-pass filtering means and the phase of the output signal of the tracking band-pass filtering means, thereby producing an output signal responsive to the difference of both phases; and means responsive to said output error signal for deriving a demodulated signal.
Claim 8
Independent Claim
175 words
A system for demodulating angle-modulated signals comprising: tracking band-pass filtering means supplied with an angle-modulated input signal, said filter means having a pass band with a center frequency which is variably controlled responsive to a control signal; first amplitude limiting means for limiting the amplitude of the angle-modulated input signal; phase-shifting means for establishing a phase difference of 90° between a signal passing through said tracking band-pass filtering means and a signal passing through said amplitude limiting means; first phase comparing means responsive to the 90° phase difference signals for producing an output error signal in accordance with said phase difference; means responsive to said output error signal for controlling said tracking band-pass filtering means; second phase comparing means for comparing the phase of the input angle-modulated signal to be supplied to the tracking band-pass filtering means and the phase of the output signal of the tracking band-pass filtering means, thereby producing an output signal responsive to the difference of both phases; and means responsive to said output error signal for deriving a demodulated signal.
Claim 9
Independent Claim
154 words
A system for demodulating angle-modulated signals comprising: tracking band-pass filtering means supplied with an angle-modulated input signal, said filter means having a pass band with a center frequency which is variably controlled responsive to a control signal; first amplitude limiting means for limiting the amplitude of the angle-modulated input signal; phase-shifting means for establishing a phase difference of 90° between a signal passing through said tracking band-pass filtering means and a signal passing through said amplitude means; phase comparing means responsive to the 90° phase difference signals for producing an output error signal in accordance with said phase difference; means responsive to said output error signal for controlling said tracking band-pass filtering means; and means responsive to said output error signal for deriving a demodulated signal, said demodulated signal deriving means including a double integral circuit for removing unnecessary carrier components and higher harmonics thereof from the output signal of the phase comparing means.
Claim 10
Independent Claim
154 words
A system for demodulating angle-modulated signals comprising: tracking band-pass filtering means supplied with an angle-modulated input signal, said filter means having a pass band with a center frequency which is variably controlled responsive to a control signal; first amplitude limiting means for limiting the amplitude of the angle-modulated input signal; phase-shifting means for establishing a phase difference of 90° between a signal passing through said tracking band-pass filtering means and a signal passing through said amplitude means; phase comparing means responsive to the 90° phase difference signals for producing an output error signal in accordance with said phase difference; means responsive to said output error signal for controlling said tracking band-pass filtering means; and means responsive to said output error signal for deriving a demodulated signal, said demodulated signal deriving means including a double integral circuit for removing unnecessary carrier components and higher harmonics thereof from the output signal of the phase comparing means.
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) | 1981-03-13 | 1981-09-12 | 1982-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-03-13 | 1985-09-12 | 1986-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-03-13 | 1989-09-12 | 1990-03-14 | $7700.00 | Window Closed / Lapsed |