US4193035A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit arrangement for receiving one of the sidebands from a double sideband signal
Assignee: US Philips Corp
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Filing: 1977-11-17
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Granted: 1980-03-11
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Expires: 1997-11-17
Abstract
Abstract The invention relates to an AM-receiver for receiving one of the sidebands of a double sideband signal, for example, in medium wave or short wave broadcast. Selective fading is avoided by the reception of one sideband only. The circuit can substantially be implemented from input to output in integrated circuit technology. It enables the high-grade reception of the double sideband AM-signals without crosstalk or squal.
Inventors
- 👤 Hermann Berger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 13:47
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/06; H04B1/16; H04B1/30; H04B1/302
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
187 words
A circuit arrangement for receiving one of the sidebands of a double sideband signal, comprising two first mixing stages means for mixing the double sideband signal with each one of two locally produced radio frequency oscillations having the same frequency as the carrier frequency of said double sideband signal and phases shifted 90° relative to one another, first and second low pass filter means for filtering the output signals of the two mixing stages respectively, two second mixing stages means respectively coupled to said filters for mixing the filter output signals with either one of two locally produced low-frequency oscillations having the same frequency which is at least equal to the upper frequency of the baseband signal and shifted in phase 90° relative to one another, means for combining the output signals of the two second mixing stages, a third low-pass filter means coupled to said combining means for suppressing signals having a frequency above the frequency of the local low frequency oscillation, and a last mixing stage means for mixing the output signals of the third low-pass filter with one of the local low frequency oscillations.
Claim 2
Dependent Claim
187 words
A circuit arrangement for receiving one of the sidebands of a double sideband signal, comprising two first mixing stages means for mixing the double sideband signal with each one of two locally produced radio frequency oscillations having the same frequency as the carrier frequency of said double sideband signal and phases shifted 90° relative to one another, first and second low pass filter means for filtering the output signals of the two mixing stages respectively, two second mixing stages means respectively coupled to said filters for mixing the filter output signals with either one of two locally produced low-frequency oscillations having the same frequency which is at least equal to the upper frequency of the baseband signal and shifted in phase 90° relative to one another, means for combining the output signals of the two second mixing stages, a third low-pass filter means coupled to said combining means for suppressing signals having a frequency above the frequency of the local low frequency oscillation, and a last mixing stage means for mixing the output signals of the third low-pass filter with one of the local low frequency oscillations.
Claim 3
Dependent Claim
34 words
A circuit arrangement as claimed in claim 1, further comprising a fourth low-pass filter coupled to said last mixing stage and having a cutoff frequency which corresponds to that of the third low-pass filter.
Claim 4
Dependent Claim
44 words
A circuit arrangement as claimed in claim 1 for receiving one from a plurality of double sideband signals whose carrier frequencies are equally spaced, wherein the frequency of the locally produced low-frequency oscillations corresponds to half the frequency spacing of two adjacent carrier frequencies.
Claim 5
Dependent Claim
45 words
A circuit arrangement as claimed in claim 1 for receiving double-sideband signals with carriers, further comprising a tunable oscillator circuit means for supplying the radio frequency oscillations, and phase control circuit means for providing that the oscillator frequency is synchronized with the received carrier frequency.
Claim 6
Dependent Claim
51 words
A circuit arrangement as claimed in claim 4, wherein the phase control circuit means comprises an input means for receiving a D.C. voltage produced by the mixing stage whose input is supplied with the locally produced radio frequency oscillation with a phase shift of approximately 90° relative to the carrier oscillation.
Claim 7
Dependent Claim
45 words
A circuit arrangement as claimed in claim 1, further comprising means for using as a gain control voltage a D.C. voltage produced by the mixing stage whose input is supplied with the locally produced radio frequency oscillation having the same phase as the carrier oscillation.
Claim 8
Dependent Claim
17 words
A circuit arrangement as claimed in claim 1, wherein the third low-pass filter comprises a gyrator filter.
Claim 9
Dependent Claim
18 words
A circuit arrangement as claimed in claim 1, wherein the first and second low-pass filters comprise gyrator filters.
Claim 10
Dependent Claim
17 words
A circuit arrangement as claimed in claim 2, wherein the fourth low-pass filter comprises a gyrator filter.
Claim 11
Dependent Claim
25 words
A circuit arrangement as claimed in claim 1, further comprising a control circuit means for adjusting the oscillator for locally producing the low frequency oscillation.
Claim 12
Dependent Claim
34 words
A circuit arrangement as claimed in claim 1, wherein the combining means comprises means for providing that the output signals of the second mixing stages can optionally be added or subtracted from one another.
Claim 13
Dependent Claim
23 words
A circuit arrangement as claimed in claim 1, further comprising D.C. blocking capacitors coupled to the outputs of the first mixing stages respectively.
Claim 14
Dependent Claim
25 words
A circuit as claimed in claim 1, further comprising a control circuit means for adjusting the first attenuation pole of the third low pass filter.
References Cited (Backward Citations)
US3611144A
Cited
US3969675A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-03-11 | 1983-09-10 | 1984-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-03-11 | 1987-09-10 | 1988-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-03-11 | 1991-09-10 | 1992-03-11 | $7700.00 | Window Closed / Lapsed |