US4776040A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Superheterodyne receiver
Assignee: Pioneer Corp
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Filing: 1987-08-12
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Granted: 1988-10-04
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Expires: 2007-08-12
Abstract
Abstract A superheterodyne receiver in which unwanted lowering of the RF gain due to the presence of an interference signal outside the band of the desired signal is substantially eliminated. Levels of the outputs of both the RF amplifier and first mixer of the circuit are detected. The two level detection signals so produced are summed, and the sum signal applied to the gain control input terminal of the RF amplifier.
Inventors
- 👤 Toshihito Ichikawa
- 👤 Hideki Iwasaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 05:25
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/3052
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
262 words
A double superheterodyne receiver comprising: an aperiodic RF amplifier having a gain control input and including a field-effect transistor receiving an RF signal at its gate; a variable-frequency local oscillator; first mixing means having a first input coupled to an output of said aperiodic RF amplifier and a second input coupled to an output of said variable-frequency local oscillator; first level detecting means having an input coupled to an output of said first mixing means; first bandpass filter means coupled in series with said first mixing means, said output of said first mixing means being provided at an input terminal of said first bandpass filter means; second level detecting means having an input coupled to said output of said aperiodic RF amplifier; a summing circuit having a first input coupled to an output of said first level detecting means and a second input coupled to an output of said second level detecting means, an output of said summing circuit being coupled to said gain control input of said aperiodic RF amplifier; a fixed local oscillator; second mixing means having a first input coupled to an output of said fixed local oscillator and a second input coupled to said output of said first mixing means; a second bandpass filter having an input coupled to an output of said second mixing means; an IF amplifier and detector having an input coupled to an output of said second mixing means; and an AGC amplifier, coupled to an output of said IF amplifier and detector for controlling an amplification factor of said IF amplifier and detector.
Claim 2
Dependent Claim
262 words
A double superheterodyne receiver comprising: an aperiodic RF amplifier having a gain control input and including a field-effect transistor receiving an RF signal at its gate; a variable-frequency local oscillator; first mixing means having a first input coupled to an output of said aperiodic RF amplifier and a second input coupled to an output of said variable-frequency local oscillator; first level detecting means having an input coupled to an output of said first mixing means; first bandpass filter means coupled in series with said first mixing means, said output of said first mixing means being provided at an input terminal of said first bandpass filter means; second level detecting means having an input coupled to said output of said aperiodic RF amplifier; a summing circuit having a first input coupled to an output of said first level detecting means and a second input coupled to an output of said second level detecting means, an output of said summing circuit being coupled to said gain control input of said aperiodic RF amplifier; a fixed local oscillator; second mixing means having a first input coupled to an output of said fixed local oscillator and a second input coupled to said output of said first mixing means; a second bandpass filter having an input coupled to an output of said second mixing means; an IF amplifier and detector having an input coupled to an output of said second mixing means; and an AGC amplifier, coupled to an output of said IF amplifier and detector for controlling an amplification factor of said IF amplifier and detector.
Claim 3
Dependent Claim
54 words
The double superheterodyne receiver of claim 1, wherein, for a gain G 1 of said aperiodic RF amplifier, a gain G 2 of said first mixing means, a gain G 11 of said first level detecting means, and a gain G 10 of said second level detecting means: G.sub.1 +G.sub.10 <G.sub.1 +G.sub.2 +G.sub.4 +G.sub.11.
Claim 4
Dependent Claim
13 words
The double superheterodyne receiver of claim 2, wherein G 10 =G 11 .
Claim 5
Dependent Claim
17 words
The double superheterodyne receiver of claim 2, wherein said first mixing means comprises a double balanced mixer.
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) | 1991-10-04 | 1992-04-04 | 1992-10-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-10-04 | 1996-04-04 | 1996-10-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-10-04 | 2000-04-04 | 2000-10-04 | $7700.00 | Window Closed / Lapsed |