GB611078A - Improvements in and relating to frequency modulation radio receivers - Google Patents
Improvements in and relating to frequency modulation radio receiversInfo
- Publication number
- GB611078A GB611078A GB6273/46A GB627346A GB611078A GB 611078 A GB611078 A GB 611078A GB 6273/46 A GB6273/46 A GB 6273/46A GB 627346 A GB627346 A GB 627346A GB 611078 A GB611078 A GB 611078A
- Authority
- GB
- United Kingdom
- Prior art keywords
- filter
- frequency modulation
- detector
- frequency
- tune
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
- H03D3/00—Demodulation of angle-, frequency- or phase- modulated oscillations
- H03D3/02—Demodulation of angle-, frequency- or phase- modulated oscillations by detecting phase difference between two signals obtained from input signal
- H03D3/24—Modifications of demodulators to reject or remove amplitude variations by means of locked-in oscillator circuits
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G3/00—Gain control in amplifiers or frequency changers without distortion of the input signal
- H03G3/20—Automatic control
- H03G3/22—Automatic control in amplifiers having discharge tubes
- H03G3/26—Muting amplifier when no signal is present or when only weak signals are present, or caused by the presence of noise, e.g. squelch systems
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03L—AUTOMATIC CONTROL, STARTING, SYNCHRONISATION, OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES
- H03L7/00—Automatic control of frequency or phase; Synchronisation
- H03L7/06—Automatic control of frequency or phase; Synchronisation using a reference signal applied to a frequency- or phase-locked loop
Abstract
611,078. Frequency modulation. PHILCO RADIO & TELEVISION CORPORATION. Feb. 28, 1946, No. 6273. Convention date, Feb. 28, 1945. [Class 40 (v)] Frequency modulation receivers of the kind in which a local oscillator . is synchronized with the received wave when the tuning is accurate, are provided with muting means responsive to incomplete synchronization when the receiver is off-tune. As shown, the received wave is heterodyned at the mixer I to a lower intermediate frequency which is amplified and applied to a phase detector 4. This detector is also fed from a synchronized oscillator 5 which is controlled through a quadrature circuit 6 in the manner described in Specification 639,922. The audio signal from the detector output is selected by a filter 9, amplified at 10, and fed to the reproducer 11. When the set is somewhat off tune, a supersonic beat frequency appearing in the detector output, is selected by a filter 13, rectified at 14, smoothed at the filter 15 and applied to the audio amplifier 10 to mute the receiver. The Specification includes a circuit diagram, Fig. 2 (not shown). Other types of locked-in oscillators may be employed, e.g. those described in Specifications 555,618 and 562,993, and may operate at a sub-harmonic frequency. The phase detector may be replaced by a normal discriminator.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US611078XA | 1945-02-28 | 1945-02-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB611078A true GB611078A (en) | 1948-10-25 |
Family
ID=22033634
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB6273/46A Expired GB611078A (en) | 1945-02-28 | 1946-02-28 | Improvements in and relating to frequency modulation radio receivers |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB611078A (en) |
-
1946
- 1946-02-28 GB GB6273/46A patent/GB611078A/en not_active Expired
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