GB555526A - Frequency modulation receivers - Google Patents
Frequency modulation receiversInfo
- Publication number
- GB555526A GB555526A GB4158/42A GB415842A GB555526A GB 555526 A GB555526 A GB 555526A GB 4158/42 A GB4158/42 A GB 4158/42A GB 415842 A GB415842 A GB 415842A GB 555526 A GB555526 A GB 555526A
- Authority
- GB
- United Kingdom
- Prior art keywords
- frequency
- resistances
- amplitude
- effected
- local oscillator
- 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
- H03D3/001—Details of arrangements applicable to more than one type of frequency demodulator
- H03D3/003—Arrangements for reducing frequency deviation, e.g. by negative frequency feedback
- H03D3/004—Arrangements for reducing frequency deviation, e.g. by negative frequency feedback wherein the demodulated signal is used for controlling an oscillator, e.g. the local oscillator
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Circuits Of Receivers In General (AREA)
- Transmitters (AREA)
Abstract
555,526. Frequency modulation. STANDARD TELEPHONES & CABLES, Ltd. March 28, 1942, No. 4158. Convention date, Nov. 13, 1940. [Class 40 (v)] Relates to frequency-modulation radio receivers of the kind described in Specification 489,636 in which the detected signal is fed back to modulate in degenerative phase the frequency of the local oscillator, and consists in providing means for maintaining a substantially uniform amplitude of IF carrier despite variations in incoming carrier amplitude. The incoming wave passes through a frequency changer 42 and IF amplifier 44 to two parallel-connected amplifiers 56, 57 which have their output circuits 52, 54 tuned above and below the true IF., the coils of each tuned circuit being closely coupled. The tuned circuits feed rectifiers 58, 59 and load resistances 64, 65, and the detected signal appearing across the joint resistances is fed in push-pull to amplifiers 68, 69 and to the signal reproducer. The detected signal is also fed back through a network 49 of the kind described in Specification 514,567 to modulate the frequency of the local oscillator 43 in such sense as to reduce the frequency deviation of the incoming wave. Automatic tuning correction is also effected by smoothed D.C. voltages derived from the resistances 64, 65 and applied through the leads 73 to control the local oscillator. Changes of amplitude in the wave applied to the frequency discriminator are detected across resistances 81, 82 connected in series between earth and the junction of the resistances 64, 65. Slow changes are applied through a delay diode 84 and resistance 86 to modify the gain of the frequency-changer 42 and amplifier 44. More rapid changes are substantially eliminated by negative feed-back provided by resistance 81 and stabilizing network 89. The receiver may have two frequency-changing stages, the frequencycontrol being effected at the second stage, and the amplitude control at the first. Amplitude control may be effected by a limiter.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US365424A US2272401A (en) | 1940-11-13 | 1940-11-13 | Frequency modulation receiver |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB555526A true GB555526A (en) | 1943-08-26 |
Family
ID=23438857
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB4158/42A Expired GB555526A (en) | 1940-11-13 | 1942-03-28 | Frequency modulation receivers |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US2272401A (en) |
| GB (1) | GB555526A (en) |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2527523A (en) * | 1944-08-11 | 1950-10-31 | Farnsworth Res Corp | Frequency control system |
| US2551348A (en) * | 1945-03-28 | 1951-05-01 | Philco Corp | Electrical apparatus |
| NL144559B (en) * | 1949-01-27 | Pechiney Saint Gobain | PROCESS FOR THE PREPARATION OF ACTIVE ALUMINUM OXIDE AGGLOMERATES AND FORMED ALUMINUM OXIDE AGGLOMERATES OBTAINED BY THIS PROCESS. | |
| US2692330A (en) * | 1950-05-22 | 1954-10-19 | Rca Corp | Noise reduction arrangement |
| US2676247A (en) * | 1950-07-28 | 1954-04-20 | Hartford Nat Bank & Trust Co | Circuit arrangement for silent tuning in frequency-modulation receivers |
| US3909725A (en) * | 1957-03-29 | 1975-09-30 | Massachusetts Inst Technology | Frequency modulation receiver |
| US3053981A (en) * | 1959-07-06 | 1962-09-11 | Security First Nat Bank | High-gain frequency modulation tuner |
| NL277424A (en) * | 1961-04-25 | |||
| US3231819A (en) * | 1961-09-07 | 1966-01-25 | Bell Telephone Labor Inc | Intermodulation distortion correction of angle modulated transmission system by use of nonlinear cancellation circuit |
| JPS6042533Y2 (en) * | 1977-02-23 | 1985-12-27 | 株式会社ケンウッド | FM receiver |
| US4293818A (en) * | 1979-01-22 | 1981-10-06 | International Telephone And Telegraph Corporation | Frequency modulation threshold extension demodulator utilizing frequency compression feedback with frequency drift correction |
| US4991226A (en) * | 1989-06-13 | 1991-02-05 | Bongiorno James W | FM detector with deviation manipulation |
| US5034695A (en) * | 1989-06-16 | 1991-07-23 | Owen Joseph C | Full threshold FM demodulator |
| US5691666A (en) * | 1995-06-07 | 1997-11-25 | Owen; Joseph C. | Full threshold FM deviation compression feedback demodulator and method |
| US8045947B2 (en) * | 2004-09-17 | 2011-10-25 | Massachusetts Institute Of Technology | RF power extracting circuit and related techniques |
-
1940
- 1940-11-13 US US365424A patent/US2272401A/en not_active Expired - Lifetime
-
1942
- 1942-03-28 GB GB4158/42A patent/GB555526A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| US2272401A (en) | 1942-02-10 |
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