US3593171A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Frequency discriminator having conduction controlled means
Assignee: International Standard Electric Corp
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Filing: 1969-07-15
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Granted: 1971-07-13
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Expires: 1989-07-15
Abstract
Abstract A frequency discriminator for frequency-modulated (FM) pulse signals having a steep discriminator characteristic. The FM pulse signals are amplitude limited, differentiated and then rectified. The time constant of a subsequent RC circuit and the fixed bias applied to the RC circuit are so selected to produce a linear sawtooth signal having a duration equal to the period of the FM pulse signals so that a subsequent transistor is always blocked at pulse frequencies above fmax, unblocked momentarily at pulse frequencies between fmin and fmax to pass pulses with an amplitude increasing in the negative direction linearly as the frequency decreases, and passes constant maximum negative going amplitude pulses at pulse frequencies below fmin. The discriminator output voltage is obtained by peak rectification of the pulses passed by the transistor. In another disclosed embodiment, the discriminator output voltage is passed through a low pass filter to provide the bias for the RC circuit.
Inventors
- 👤 Gerhard Gunter Gassmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:43
CPC Classifications
H; H03; H03K; H03K9/00; H03K9/06
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
119 words
A frequency discriminator for frequency-modulated pulse signals comprising: a source of frequency-modulated pulse signals having a constant amplitude; first means having an input coupled to said source to convert said pulse signals to substantially linear sawtooth signals having a duration equal to the period of said pulse signals and an output for said sawtooth signals; conduction-controlled means having an input coupled to said output of said first means and an output, said conduction controlled means being responsive to said sawtooth signals; and second means having an output and an input coupled to said output of said conduction controlled means for rectification of the output signal thereof to provide at the output of said second means the discriminator output voltage.
Claim 2
Dependent Claim
119 words
A frequency discriminator for frequency-modulated pulse signals comprising: a source of frequency-modulated pulse signals having a constant amplitude; first means having an input coupled to said source to convert said pulse signals to substantially linear sawtooth signals having a duration equal to the period of said pulse signals and an output for said sawtooth signals; conduction-controlled means having an input coupled to said output of said first means and an output, said conduction controlled means being responsive to said sawtooth signals; and second means having an output and an input coupled to said output of said conduction controlled means for rectification of the output signal thereof to provide at the output of said second means the discriminator output voltage.
Claim 3
Dependent Claim
14 words
A discriminator according to claim 1, wherein said second means includes a peak rectifier.
Claim 4
Dependent Claim
20 words
A discriminator according to claim 2, wherein said peak rectifier includes a transistor connected in a grounded collector circuit arrangement.
Claim 5
Dependent Claim
87 words
A discriminator according to claim 1, wherein said conduction controlled means includes a transistor circuit, said transistor being rendered nonconductive when the frequency of said pulse signals is above a given maximum frequency, momentarily conductive when the frequency of said pulse signals is between said given maximum frequency and a given minimum frequency to pass pulses whose amplitude increases linearly in a negative direction as the frequency of said pulse signals decrease, and saturated when the frequency of said pulse signals is below said given minimum frequency.
Claim 6
Dependent Claim
60 words
A discriminator according to claim 1, wherein said first means includes third means coupled to said source to differentiate said pulse signals; fourth means coupled to said third means to rectify said differentiated pulse signals; and fifth means having a given time constant coupled to said fourth means responsive to said rectified, differentiated pulse signals to produce said sawtooth signals.
Claim 7
Dependent Claim
31 words
A discriminator according to claim 5, wherein said fifth means includes a resistor-capacitor time constant circuit, and sixth means coupled to said time constant circuit to provide a bias potential therefore.
Claim 8
Dependent Claim
17 words
A discriminator according to claim 6, wherein said sixth means includes a source of fixed bias potential.
Claim 9
Dependent Claim
35 words
A discriminator according to claim 7, wherein said sixth means includes seventh means coupled between said second means and said time constant circuit to provide said bias potential varying according to said discriminator output voltage.
Claim 10
Dependent Claim
14 words
A discriminator according to claim 8, wherein said seventh means includes a low-pass filter.
Claim 11
Dependent Claim
152 words
A discriminator according to claim 1, wherein said first means includes a differentiator coupled to said source of pulse signals, a rectifier coupled to said differentiator, a Source of bias potential, and a resistor-capacitor time constant circuit coupled to said source of bias potential and said rectifier to produce said sawtooth signals; said conduction controlled means includes a NPN-type transistor circuit, said transistor being rendered nonconductive when the frequency of said pulse signals is above a given maximum frequency, momentarily conductive when the frequency of said pulse signals is between said given maximum frequency and a given minimum frequency to pass pulses whose amplitude increases linearly in a negative direction as the frequency of said pulse signals decrease, and saturated when the frequency of said pulse signals is below said given minimum frequency; and said second means includes a peak rectifier having a PNP-type transistor connected in a grounded collector circuit arrangement.
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) | 1974-07-12 | 1975-01-11 | 1975-07-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-07-12 | 1979-01-11 | 1979-07-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-07-12 | 1983-01-11 | 1983-07-13 | $7700.00 | Window Closed / Lapsed |