US3783388A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multiple carrier frequency modulated signal generating apparatus
Assignee: GTE Sylvania Inc
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Filing: 1972-01-20
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Granted: 1974-01-01
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Expires: 1992-01-20
Abstract
Abstract Signal generator for use in testing FM communication receivers including a triggered free-running multivibrator which may be synchronized to operate at a frequency equal to the spacing between adjacent channels of the FM receiver. An audio oscillator modulates the output of the multivibrator which output is applied to a step recovery diode. The output of the step recovery diode is a plurality of harmonics of the frequency of the multivibrator each frequency modulated at the frequency of the audio oscillator.
Inventors
- 👤 D Disinger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 04:04
CPC Classifications
H; H03; H03B; H03B19/00; H03B19/16
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
175 words
Multiple carrier frequency modulated signal generating apparatus including in combination first oscillator means operable to produce a signal of a basic frequency at an output connection; second oscillator means coupled to the first oscillator means and operable to vary the signal at the output connection of the first oscillator means from the basic frequency by a predetermined amount and at a predetermined rate; spectrum generating means including a step recovery diode operable to produce at its output electrode a plurality of harmonics of the signal applied at its input electrode; and means connecting the output connection of the first oscillator means to the input electrode of the step recovery diode for coupling the signal at the output connection of the first oscillator means to the input electrode of the step recovery diode; whereby the spectrum generating means produces a plurality of output signals each of which is a harmonic of the basic frequency varying by an amount equal to the same harmonic of the predetermined amount and at a rate equal to the predetermined rate.
Claim 2
Dependent Claim
175 words
Multiple carrier frequency modulated signal generating apparatus including in combination first oscillator means operable to produce a signal of a basic frequency at an output connection; second oscillator means coupled to the first oscillator means and operable to vary the signal at the output connection of the first oscillator means from the basic frequency by a predetermined amount and at a predetermined rate; spectrum generating means including a step recovery diode operable to produce at its output electrode a plurality of harmonics of the signal applied at its input electrode; and means connecting the output connection of the first oscillator means to the input electrode of the step recovery diode for coupling the signal at the output connection of the first oscillator means to the input electrode of the step recovery diode; whereby the spectrum generating means produces a plurality of output signals each of which is a harmonic of the basic frequency varying by an amount equal to the same harmonic of the predetermined amount and at a rate equal to the predetermined rate.
Claim 3
Dependent Claim
59 words
Multiple carrier frequency modulated signal generating apparatus in accordance with claim 1 wherein said first oscillator means includes a triggered free-running multivibrator employing first and second cross-coupled transistors, and the output connection from the first oscillator means is at the collector of the first transistor; and said second oscillator means is coupled to the base of the first transistor.
Claim 4
Dependent Claim
73 words
Multiple carrier frequency modulated signal generating apparatus in accordance with claim 2 wherein said means connecting the output connection of the first oscillator means to the input electrode of the step recovery diode includes a capacitance operable to be charged when the first transistor is in the non-conducting condition and to be discharged rapidly when the first transistor becomes conducting, thereby causing a rapid reversal of current flow through the step recovery diode.
Claim 5
Dependent Claim
63 words
Multiple carrier frequency modulated signal generating apparatus in accordance with claim 3 including signal shaping means connected to the output electrode of the step recovery diode and operable to attenuate the plurality of output signals from the spectrum generating means by an amount inversely related to the frequency of the output signals whereby differences in the amplitudes of the output signals are reduced.
Claim 6
Dependent Claim
63 words
Multiple carrier frequency modulated signal generating apparatus in accordance with claim 4 and operable for testing an FM receiver wherein said first oscillator means is adapted to be synchronized by a reference frequency signal to produce a signal of a basic frequency equal to the spacing between carrier frequencies of the FM receiver; and said second Oscillator means operates at an audio frequency.
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) | 1976-12-31 | 1977-07-02 | 1978-01-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-31 | 1981-07-02 | 1982-01-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-31 | 1985-07-02 | 1986-01-01 | $7700.00 | Window Closed / Lapsed |