US4042782A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High selectivity radio receiver
Assignee: Individual
•
Filing: 1976-04-28
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Granted: 1977-08-16
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Expires: 1996-04-28
Abstract
Abstract A superheterodyne receiver for double sideband signals employing two filters having bandwidths encompassing the carrier and sidebands, and providing equal attenuation of signals at the desired frequency and unequal attenuation of signals at other frequencies. The filters respectively drive a pair of detector circuits which are connected to one another in series, each detector including a transistor biased to the point of collector conduction for efficient detection. The series connected detectors provide audio output signals attenuated by the greater of the attenuations provided by the two filters. The equal attenuation provided at the desired frequency is 6 db or less, and attenuation by one or the other of the filters increases rapidly as the frequency deviates from that of the desired signal. For example, in the disclosed embodiment, attenuation is 30 db at one kHz, and 56db for signals 2kHz from the desired signal. The receiver of the invention is also uniquely suited for employment of digital frequency readout and for reception of stereo radio signals.
Inventors
- 👤 Joseph A. Worcester
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 10:07
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/06; H04B1/16; H04B1/26; H04B1/28; H04B1/1646; H04B1/1661
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
105 words
A superheterodyne radio receiver for reception of signals having upper and lower sidebands containing audio program materials, said receiver comprising: a. means for translating a desired signal to a fixed intermediate frequency; b. first and second selective filters each connected to receive input signals from said translating means, said filters providing equal attenuation of input signals at said fixed frequency and unequal attenuation of input signals at other than said fixed frequency; and c. demodulation means providing audio output signals in response to inputs from said filters, said output signals being attenuated by the greater of the attenuations of said input signals by said filters.
Claim 2
Dependent Claim
105 words
A superheterodyne radio receiver for reception of signals having upper and lower sidebands containing audio program materials, said receiver comprising: a. means for translating a desired signal to a fixed intermediate frequency; b. first and second selective filters each connected to receive input signals from said translating means, said filters providing equal attenuation of input signals at said fixed frequency and unequal attenuation of input signals at other than said fixed frequency; and c. demodulation means providing audio output signals in response to inputs from said filters, said output signals being attenuated by the greater of the attenuations of said input signals by said filters.
Claim 3
Dependent Claim
24 words
The invention according to claim 1 wherein said demodulation means comprises first and second detector circuits connected to said first and second filters, respectively.
Claim 4
Dependent Claim
17 words
The invention according to claim 2 wherein said detector circuits are connected to one another in series.
Claim 5
Dependent Claim
18 words
The invention according to claim 3 wherein said detector circuits each comprise a transistor and a biasing means.
Claim 6
Dependent Claim
41 words
The invention according to claim 4 wherein said first and second filters each include an output winding connected at one end to the base of the transistor and at the other end to the biasing means of the respective detector circuits.
Claim 7
Dependent Claim
22 words
The invention according to claim 4 wherein said transistors are biased by said biasing means just to the point of collector conduction.
Claim 8
Dependent Claim
23 words
The invention according to claim 1 and further including means providing a digital readout of the frequency of the carrier signal being received.
Claim 9
Dependent Claim
37 words
The invention according to claim 1 wherein the band widths of said filters on opposite sides of said fixed frequency are mutually exclusive and substantially equal to the respective bandwidths of said sidebands at said equal attenuation.
Claim 10
Dependent Claim
19 words
The invention according to claim 8 wherein the level of said equal attenuation is not greater than about 6db.
Claim 11
Dependent Claim
34 words
The invention according to claim 1 wherein said demodulation means includes first and second output terminals at which audio output signals carrying program material from amplitude modulated and frequency modulated signals, respectively are provided.
Claim 12
Dependent Claim
39 words
The invention according to claim 10 and further including a matrix natwork connected to each of said first and second output terminals, and providing separate outputs carrying the program material initially contained on the upper and lower sidebands, respectively.
Claim 13
Dependent Claim
149 words
A superheterodyne radio receiver for the reception of stereo radio signals comprising a carrier amplitude modulated by L+R program material and frequency modulated by L-R program material, said receiver comprising: a. signal translating means for changing received radio frequency signals to an intermediate frequency; b. first and second selective filters each connected to receive input signals from said translating means, said filters providing equal attenuation of input signals at said intermediate frequency and unequal attenuation of input signals at other than said intermediate frequency; c. demodulation means having first and second output terminals, and constructed and arranged to provide at said first terminal an audio signal containing the L+R program material, and at said second terminal an audio signal containing the L-R program material; and d. matrixing circuiry to which said first and second output terminals are connected and adapted to provide separate L and R audio output signals.
Claim 14
Dependent Claim
149 words
A superheterodyne radio receiver for the reception of stereo radio signals comprising a carrier amplitude modulated by L+R program material and frequency modulated by L-R program material, said receiver comprising: a. signal translating means for changing received radio frequency signals to an intermediate frequency; b. first and second selective filters each connected to receive input signals from said translating means, said filters providing equal attenuation of input signals at said intermediate frequency and unequal attenuation of input signals at other than said intermediate frequency; c. demodulation means having first and second output terminals, and constructed and arranged to provide at said first terminal an audio signal containing the L+R program material, and at said second terminal an audio signal containing the L-R program material; and d. matrixing circuiry to which said first and second output terminals are connected and adapted to provide separate L and R audio output signals.
Claim 15
Dependent Claim
40 words
The invention according to claim 12 wherein said demodulation means is constructed and arranged to provide audio signals at both of said output terminals which are attenuated by the greater of the attenuations of said input signals by said filters.
Claim 16
Dependent Claim
24 words
The invention according to claim 13 wherein said demodulation means comprises first and second detector circuits connected to said first and second filters, respectively.
Claim 17
Dependent Claim
28 words
The invention according to claim 14 wherein said detector circuits are connected to one another in series and one of said output terminals is at the series connection.
Claim 18
Dependent Claim
28 words
The invention according to claim 15 wherein the bandwidths of said filters are mutually exclusive and substantially equal to the bandwidths of said sidebands at said equal attenuation.
Claim 19
Dependent Claim
19 words
The invention according to claim 16 wherein the level of said equal attenuation is not greater than about 6db.
Claim 20
Dependent Claim
18 words
The invention according to claim 17 wherein said detector circuits each comprise a transistor and a biasing means.
Claim 21
Dependent Claim
41 words
The invention according to claim 18 wherein said first and second filters each include an output winding connected at one end to the base of the transistor and at the other end to the biasing means of the respective detector circuits.
Claim 22
Dependent Claim
22 words
The invention according to claim 19 wherein said transistors are biased by said biasing means just to the point of collector conduction.
Claim 23
Dependent Claim
36 words
The invention according to claim 12 wherein said demodulation means further includes a third output terminal at which a signal representing -L-R program material is present, said third output terminal being connected to said matrixing circuitry.
References Cited (Backward Citations)
US2073344A
Cited
US3944749A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-08-15 | 1981-02-14 | 1981-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-15 | 1985-02-14 | 1985-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-15 | 1989-02-14 | 1989-08-16 | $7700.00 | Window Closed / Lapsed |