US3626331A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Audio signal processor
Assignee: Motorola Solutions Inc
•
Filing: 1970-06-08
•
Granted: 1971-12-07
•
Expires: 1990-06-08
Abstract
Abstract A modulating processing system for a phase or frequency modulated transmitter includes a differentiator and limiter for controlling the deviation of the modulated signal. The limiter includes a pair of emitter-coupled transistors alternately biased by an input signal between cutoff and conduction. A constant current source is coupled in series with the emitters of the limiter to maintain conduction at less than saturation and temperature compensation circuits are included to stabilize the operation of the system with temperature changes. The circuit is readily adapted to be formed as an integrated circuit.
Inventors
- 👤 Donald B Burns
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 10:35
CPC Classifications
H; H03; H03C; H03C3/00; H03C3/02
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
195 words
In a modulation system in which a carrier wave signal is modulated by a modulating signal, the system for controlling the deviation and audio frequency response, including in combination, input circuit means for receiving the modulating signal, differentiating means coupled to said input circuit means for producing therefrom a differentiated modulating signal, phasesplitting means coupled to said differentiating means for developing a pair of differentiated modulating signals differing in phase by approximately 180* , limiting means including a pair of transistors having common electrodes coupled together, first and second input electrodes and first and second output electrodes, circuit means coupling said phase-splitting means to said limiting means for applying one of said differentiated modulating signals to said first input electrode, and the other of said differentiated modulating signals to said second input electrode, constant current means coupled in series with said common electrodes of said limiting transistors and to a first reference potential, said pair of differentiated modulating signals acting to bias each of said limiting transistors alternately between conduction and cutoff, said constant current means acting to limit the current through said conduction one of said current-limiting transistor to a value less than saturation.
Claim 2
Dependent Claim
195 words
In a modulation system in which a carrier wave signal is modulated by a modulating signal, the system for controlling the deviation and audio frequency response, including in combination, input circuit means for receiving the modulating signal, differentiating means coupled to said input circuit means for producing therefrom a differentiated modulating signal, phasesplitting means coupled to said differentiating means for developing a pair of differentiated modulating signals differing in phase by approximately 180* , limiting means including a pair of transistors having common electrodes coupled together, first and second input electrodes and first and second output electrodes, circuit means coupling said phase-splitting means to said limiting means for applying one of said differentiated modulating signals to said first input electrode, and the other of said differentiated modulating signals to said second input electrode, constant current means coupled in series with said common electrodes of said limiting transistors and to a first reference potential, said pair of differentiated modulating signals acting to bias each of said limiting transistors alternately between conduction and cutoff, said constant current means acting to limit the current through said conduction one of said current-limiting transistor to a value less than saturation.
Claim 3
Dependent Claim
70 words
The modulation processing system of claim 1 wherein, said constant current means includes a transistor having a first electrode coupled to said common electrodes, a second electrode coupled to said first reference potential and a control electrode, first bias circuit means coupled to said control electrode for applying a bias potential thereto for establishing the value of current through said first and second electrodes of said constant current means transistor.
Claim 4
Dependent Claim
140 words
The modulation system of claim 2 wherein said first electrode of said constant current meanS transistor is a collector electrode, said second electrode of said constant current means transistor is an emitter electrode and said control electrode of said constant current means transistor is a base electrode, said first bias circuit means includes a first bias diode having first and second electrodes and a plurality of voltage divider resistors connected in series between said first reference potential and a second reference potential and with said first electrode of said first bias diode being connected to said base electrode of said constant current means transistor, the voltage drop of said first bias diode changing with temperature in the same manner as the base-to-emitter voltage drop of said constant current means transistor to compensate said constant current means for changes in temperature.
Claim 5
Dependent Claim
141 words
The modulation signal processing system of claim 3, wherein said phase-splitting means includes first and second phase-splitting transistors each having one base, emitter and collector electrodes, said emitter electrodes of said phase-splitting transistors being coupled together to form an emitter-coupled amplifier, said collector electrodes of said phase-splitting transistors being individually coupled to separate ones of said first and second input electrodes of said pair of limiting means transistors, said base electrode of said first phase-splitting transistor being coupled to said differentiating means, and attenuation means coupling said base electrode of said second phase-splitting transistor to said differentiating means to attenuate signals applied to said second phase-splitting transistor, whereby the differentiated modulating signals applied to said base electrode of said second phase-shifting transistor have a smaller magnitude than the differentiated modulating signals applied to said base electrode of said first phase-splitting transistor.
Claim 6
Dependent Claim
137 words
The modulation system of claim 4 wherein, said phase-splitting means further includes a current-regulating transistor coupling said emitter electrodes of said phase-splitting transistor to said first reference potential, said current-regulating transistor including a base electrode coupled to said first electrode of said first bias diode, said first bias diode providing temperature compensation for said current-regulating transistor, a second bias diode coupled in series with a second plurality of voltage divider resistors between said first and second reference potentials, said second bias diode begin coupled to said base electrode of said first and second phase-splitting transistors to provide a bias current therefore, the voltage drop of said first bias diode changing with temperature in the same manner as the base-to-emitter voltage drop of said first and second phase-splitting transistors to compensate said phase-splitting means for changes in temperature.
Claim 7
Dependent Claim
24 words
The modulation system of claim 5 wherein, said input circuit means includes amplifying means coupled to said differentiating means for amplifying the modulating signal.
Claim 8
Dependent Claim
37 words
The modulation system of claim 6 further including output circuit means having filter means coupled to one of said first and second output electrodes of said limiting means transistors and output means coupled to said filter means.
Claim 9
Dependent Claim
80 words
The modulation system of claim 1 wherein, said differentiating means includes a capacitor portion and an impedance portion, said differentiating means further including a first terminal coupled to said input circuit means and a second terminal, said capacitor portion being coupled between said first and second terminals, said input circuit means, said first and second terminals, said impedance portion, said phase-splitting means, said circuit means, said limiting means and said constant current means being formed as a monolithic integrated circuit.
Claim 10
Dependent Claim
92 words
The modulation processing system of claim 8 wherein said constant current means includes a transistor formed as a portion of said integrated circuit structure and having a first electrode couplEd in series with said common electrodes, a second electrode coupled to said first reference potential and a control electrode, first bias circuit means formed as a portion of said integrated circuit structure and coupled to said control electrode for applying a bias potential thereto for establishing the value of current through said first and second electrodes of said constant current means transistor.
Claim 11
Dependent Claim
181 words
In a modulation system in which a carrier wave signal is frequency or phase modulated by a modulating signal, the system for processing the modulating signal to control the deviation and audio response of the modulated carrier wave including in combination, circuit means having an input for receiving the modulating signal and first and second outputs, said circuit means including differentiating and phase-splitting means for differentiating said modulating signal and producing at said outputs differentiated modulating signals differing in phase by approximately 180* , and limiting means having first and second limiter inputs individually coupled to said first and second outputs of said circuit means and a limiter output, said limiting means including first and second semiconductor devices having control electrodes individually coupled to said first and second limiter inputs and common electrodes connected together, and constant current means connected in series between said common electrodes and a reference potential, said semiconductor devices limiting the differentiated modulating signals differing in phase which are applied to said first and second limiter inputs and providing a symmetrically limited signal at said limiter output.
Claim 12
Dependent Claim
181 words
In a modulation system in which a carrier wave signal is frequency or phase modulated by a modulating signal, the system for processing the modulating signal to control the deviation and audio response of the modulated carrier wave including in combination, circuit means having an input for receiving the modulating signal and first and second outputs, said circuit means including differentiating and phase-splitting means for differentiating said modulating signal and producing at said outputs differentiated modulating signals differing in phase by approximately 180* , and limiting means having first and second limiter inputs individually coupled to said first and second outputs of said circuit means and a limiter output, said limiting means including first and second semiconductor devices having control electrodes individually coupled to said first and second limiter inputs and common electrodes connected together, and constant current means connected in series between said common electrodes and a reference potential, said semiconductor devices limiting the differentiated modulating signals differing in phase which are applied to said first and second limiter inputs and providing a symmetrically limited signal at said limiter output.
Claim 13
Dependent Claim
80 words
The processing system of claim 10 wherein said first and second semiconductor devices are first and second transistors each having base, emitter, and collector electrodes, with said base electrodes forming control electrodes and being coupled to said first and second inputs and said emitter electrodes of said transistors forming said common electrodes, said differentiated modulating signals rendering said transistors alternately conductive and cutoff, and said constant current means acting to limit the current through the conducting one of said transistors.
Claim 14
Dependent Claim
45 words
The processing system of claim 11 wherein said phase-splitting means includes first and second transistors each having base, emitter, and collector electrodes, with said emitter electrodes connected together to form an emitter-coupled amplifier, and said collector electrodes being coupled to said first and second outputs.
Claim 15
Dependent Claim
33 words
The processing system of claim 11 wherein said first and second transistors of said limiting means, and said first and second transistors of said phase-splitting means are constructed as a monolithic integrated circuit.
References Cited (Backward Citations)
US3109991A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-06 | 1975-06-07 | 1975-12-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-06 | 1979-06-07 | 1979-12-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-06 | 1983-06-07 | 1983-12-07 | $7700.00 | Window Closed / Lapsed |