US3899429A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pulse-frequency-modulation signal transmission system
Assignee: NEC Corp
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Filing: 1972-10-24
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Granted: 1975-08-12
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Expires: 1992-10-24
Abstract
Abstract A pulse-frequency modulation signal eliminating the need for transmitting reference timing pulses. The level of the information signal to be transmitted is compared against the level of a ramp signal to generate a narrow output pulse which resets the ramp signal generator. The time spacing of the narrow pulses is a function of the level of the information signal. At the receiver end the received time spaced pulses control the resetting of a ramp generator whose output is filtered to reconstruct the original information signal. Each time spaced pulse thus acts as the time reference for the next received pulse.
Inventors
- 👤 Yoshito Ueno
- 👤 Mitsuo Kajitani
- 👤 Yoshio Ohgushi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 03:19
CPC Classifications
H; H04; H04B; H04B14/00; H04B14/02; H04B14/026
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
165 words
A PULSE-FREQUENCY-MODULATION SYSTEM FOR TRANSMITTING AND RECEIVING ANALOG SIGNALS AND THE LIKE WHEREIN THE MAGNITUDE OF THE SAMPLED ANALOG SIGNAL IS REPRESENTED BY THE TIME SPACING BETWEEN SUCCESSIVELY TRANSMITTED NARROW PULSES, SAID SYSTEM COMPRISING: A SAWTOOTH GENERATOR, CIRCUIT MEANS FOR COMPARING THE ANALOG SIGNAL TO BE TRANSMITTED WITH THE OUTPUT OF SAID SAWTOOTH GENERATOR, PULSE GENERATING MEANS COUPLED TO SAID COMPARISON CIRCUIT FOR GENERATING A NARROW PULSE WHEN THE LEVEL DIFFERENCE OF THE TWO INPUTS TO THE COMPARISON CIRCUIT HAVE A PREDETERMINED RELATIONSHIP, THE INPUT OF SAID SAWTOOTH GENERATOR BEING COUPLED TO THE OUTPUT OF SAID PULSE GENERATOR WHICH IS ADAPTED TO INSTANTANEOUSLY RESET THE RAMP SIGNAL OF SAID SAWTOOTH GENERATOR TO ZERO LEVEL BY SAID NARROW PULSE AND THEREBY INSTANTANEOUSLY INITIATING SUCCESSIVE RAMP SIGNAL AFTER SAID RESETTING OPERAION TO ENABLE SAID CIRCUIT MEANS TO PERFORM A SUBSEQUENT COMPARISON OPERATION, WHEREBY ADJACENT NARROW PULSES ARE TIME-SPACED RELATIVE TO ONE ANOTHER AS A FUNCTION OF THE INSTANTANEOUS LEVEL OF THE ANALOG INPUT SIGNAL TO BE TRANSMITTED.
Claim 2
Dependent Claim
165 words
A PULSE-FREQUENCY-MODULATION SYSTEM FOR TRANSMITTING AND RECEIVING ANALOG SIGNALS AND THE LIKE WHEREIN THE MAGNITUDE OF THE SAMPLED ANALOG SIGNAL IS REPRESENTED BY THE TIME SPACING BETWEEN SUCCESSIVELY TRANSMITTED NARROW PULSES, SAID SYSTEM COMPRISING: A SAWTOOTH GENERATOR, CIRCUIT MEANS FOR COMPARING THE ANALOG SIGNAL TO BE TRANSMITTED WITH THE OUTPUT OF SAID SAWTOOTH GENERATOR, PULSE GENERATING MEANS COUPLED TO SAID COMPARISON CIRCUIT FOR GENERATING A NARROW PULSE WHEN THE LEVEL DIFFERENCE OF THE TWO INPUTS TO THE COMPARISON CIRCUIT HAVE A PREDETERMINED RELATIONSHIP, THE INPUT OF SAID SAWTOOTH GENERATOR BEING COUPLED TO THE OUTPUT OF SAID PULSE GENERATOR WHICH IS ADAPTED TO INSTANTANEOUSLY RESET THE RAMP SIGNAL OF SAID SAWTOOTH GENERATOR TO ZERO LEVEL BY SAID NARROW PULSE AND THEREBY INSTANTANEOUSLY INITIATING SUCCESSIVE RAMP SIGNAL AFTER SAID RESETTING OPERAION TO ENABLE SAID CIRCUIT MEANS TO PERFORM A SUBSEQUENT COMPARISON OPERATION, WHEREBY ADJACENT NARROW PULSES ARE TIME-SPACED RELATIVE TO ONE ANOTHER AS A FUNCTION OF THE INSTANTANEOUS LEVEL OF THE ANALOG INPUT SIGNAL TO BE TRANSMITTED.
Claim 3
Dependent Claim
42 words
The device of claim 1 wherein said pulse generator is a monostable multivibrator adapted to generate narrow pulses of constant pulse width each time the level of the signal to be transmitted is equal to the output level of said saw-tooth generator.
Claim 4
Dependent Claim
42 words
The device of claim 1 further comprising an amplifier coupled to the output of said pulse generator; laser diode means coupled to said amplifier for generating a light pulse output; lens means for focusing and transmitting the output of said laser diode.
References Cited (Backward Citations)
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US3366881A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-11 | 1979-02-10 | 1979-08-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-11 | 1983-02-10 | 1983-08-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-11 | 1987-02-10 | 1987-08-12 | $7700.00 | Window Closed / Lapsed |