US3878467A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tuning system for AM/FM receivers
Assignee: Motorola Solutions Inc
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Filing: 1973-06-06
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Granted: 1975-04-15
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Expires: 1993-06-06
Abstract
Abstract An AM and FM receiver wherein the local oscillator of the AM receiver is tuned by manual means, such as pushbuttons, and the variable frequency AC signal is taken from the local oscillator, converted to a DC signal by a discriminator and utilized to tune variable capacitance diodes in the front end of the FM receiver. The DC signal may also be utilized to control variable capacitance diodes in the front end of the AM receiver.
Inventors
- 👤 Peter St C Manson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:08
CPC Classifications
H; H03; H03J; H03J7/00; H03J7/02; H03J7/04; H03J7/08; H03D; H03D3/00; H03D3/02; H03D3/04; H03J3/00; H03J3/02; H03J3/16; H03J3/18; H03J3/185; H03J7/18; H03J7/20; H03J7/24; H03J7/26; H03K; H03K7/00; H03K7/06
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
236 words
A tuning system for a wave signal receiver including in combination: manually tunable oscillator means providing an AC signal tunable through a range of frequencies; frequency detector means connected to receive the AC signal from said oscillator means for converting the AC signal to a DC signal varying in amplitude in response to variations in the frequency of the AC signal produced by tuning said oscillator means; said frequency detector means including a monostablE circuit for converting the AC signal to DC pulses, an integrator circuit connected to receive the DC pulses and provide a DC signal, a differential amplifier including a pair of transistors having a reference voltage connected to one input thereof and said DC signal from said integrator circuit connected to the other input thereof and feedback circuit means connected between said differential amplifier means and said monostable circuit for increasing the DC pulse width from said monostable circuit in response to AC signals in the high end of the frequency band being connected thereto from said oscillator means; variable capacitance means connected to the front end of the wave signal receiver for tuning the front end in response to a voltage applied to said variable capacitance means; and means connecting the DC signal from said differential amplifier means to said variable capacitance means for varying the tuning of the receiver front end in response to manual tuning of said local oscillator means.
Claim 2
Dependent Claim
236 words
A tuning system for a wave signal receiver including in combination: manually tunable oscillator means providing an AC signal tunable through a range of frequencies; frequency detector means connected to receive the AC signal from said oscillator means for converting the AC signal to a DC signal varying in amplitude in response to variations in the frequency of the AC signal produced by tuning said oscillator means; said frequency detector means including a monostablE circuit for converting the AC signal to DC pulses, an integrator circuit connected to receive the DC pulses and provide a DC signal, a differential amplifier including a pair of transistors having a reference voltage connected to one input thereof and said DC signal from said integrator circuit connected to the other input thereof and feedback circuit means connected between said differential amplifier means and said monostable circuit for increasing the DC pulse width from said monostable circuit in response to AC signals in the high end of the frequency band being connected thereto from said oscillator means; variable capacitance means connected to the front end of the wave signal receiver for tuning the front end in response to a voltage applied to said variable capacitance means; and means connecting the DC signal from said differential amplifier means to said variable capacitance means for varying the tuning of the receiver front end in response to manual tuning of said local oscillator means.
Claim 3
Dependent Claim
31 words
An improved tuning system as claimed in claim 1 wherein the tuning system is incorporated in an AM and FM receiver and the local oscillator means includes an AM local oscillator.
Claim 4
Dependent Claim
46 words
The tuning system as claimed in claim 2 wherein the variable capacitance means connected to a receiver front end include voltage variable capacitance diodes connected in tuned circuits of radio frequency amplifier means, mixer means and local oscillator means of the FM portion of the receiver.
Claim 5
Dependent Claim
44 words
The tuning system as claimed in claim 1 wherein the monostable circuit includes a pair of transistors and the means feeding back a portion of the DC signal includes an emitter follower circuit in the base circuit of one of said pair of transistors.
References Cited (Backward Citations)
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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) | 1978-04-14 | 1978-10-14 | 1979-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-14 | 1982-10-14 | 1983-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-14 | 1986-10-14 | 1987-04-15 | $7700.00 | Window Closed / Lapsed |