GB481888A - Improvements relating to frequency selective systems and to systems for the reception of frequency-modulated waves - Google Patents
Improvements relating to frequency selective systems and to systems for the reception of frequency-modulated wavesInfo
- Publication number
- GB481888A GB481888A GB25444/36A GB2544436A GB481888A GB 481888 A GB481888 A GB 481888A GB 25444/36 A GB25444/36 A GB 25444/36A GB 2544436 A GB2544436 A GB 2544436A GB 481888 A GB481888 A GB 481888A
- Authority
- GB
- United Kingdom
- Prior art keywords
- valve
- frequency
- grid
- inductance
- capacity
- 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
- 230000003472 neutralizing effect Effects 0.000 abstract 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B14/00—Transmission systems not characterised by the medium used for transmission
- H04B14/002—Transmission systems not characterised by the medium used for transmission characterised by the use of a carrier modulation
- H04B14/006—Angle modulation
-
- 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
- H03D3/06—Demodulation of angle-, frequency- or phase- modulated oscillations by detecting phase difference between two signals obtained from input signal by combining signals additively or in product demodulators
- H03D3/12—Demodulation of angle-, frequency- or phase- modulated oscillations by detecting phase difference between two signals obtained from input signal by combining signals additively or in product demodulators by means of discharge tubes having more than two electrodes
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Power Engineering (AREA)
- Amplifiers (AREA)
- Near-Field Transmission Systems (AREA)
Abstract
481,888. Wireless receiving systems. STANDARD TELEPHONES & CABLES, Ltd. Sept. 18, 1936, No. 25444. Convention date, Jan. 23. [Class 40 (v)] A demodulator for frequency-modulated waves comprises a valve with two grids normally biassed to prevent anode current flow and adapted to be excited in phase from an incoming wave or in opposite phase in dependence upon whether said wave is above or below a predetermined frequency. As shown valves 5, 6 with their outputs in push-pull are fed from a series resonant circuit comprising capacity 3 and inductance 4 and tuned to the mean incoming frequency. The cathode 10 of valve 5 is connected to the outer end of capacity 3, the grid 11 to the outer end of inductance 4 and the grid 12 to the junction of the inductance and capacity. The connections of the cathode 14 and first grid 15 of valve 6 are the reverse of those of the corresponding electrodes of .valve 5. Filter elements 25, 26, 47 prevent radio frequencies from reaching the output transformer 23, 24 which passes on the resulting amplitude variations, corresponding to the modulating signal at the transmitter, to the audio frequency amplifier 45. The resonant circuit 3, 4 may be replaced by a series arrangement of two parallel tuned circuits 49, 50 and 51, 52, Fig. 4,' tuned above and below the mean received frequency, by a conjoint control 55. A separate rectifier may be provided for an amplitudemodulated carrier produced by a single valve arranged in a similar manner to those in Fig. 1 and provided with a further screen grid, Fig. 6 (not shown). In a further embodiment the demodulating valve is arranged to act also as an amplitude limiter and is provided with a neutralizing circuit, Fig. 9 (not shown).
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US60420A US2100394A (en) | 1936-01-23 | 1936-01-23 | Reception of frequency modulated waves and circuits therefor |
Publications (1)
Publication Number | Publication Date |
---|---|
GB481888A true GB481888A (en) | 1938-03-18 |
Family
ID=22029352
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB25444/36A Expired GB481888A (en) | 1936-01-23 | 1936-09-18 | Improvements relating to frequency selective systems and to systems for the reception of frequency-modulated waves |
Country Status (5)
Country | Link |
---|---|
US (1) | US2100394A (en) |
DE (1) | DE736084C (en) |
FR (1) | FR818511A (en) |
GB (1) | GB481888A (en) |
NL (1) | NL47076C (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2458943A1 (en) * | 1979-06-05 | 1981-01-02 | Victor Company Of Japan | FREQUENCY MODULATED SIGNAL DEMODULATION CIRCUIT |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE759434C (en) * | 1940-09-25 | 1953-05-04 | Lorenz A G C | Frequency-dependent voltage divider for converting a frequency-modulated alternating voltage into an amplitude-modulated one |
US2423594A (en) * | 1942-07-23 | 1947-07-08 | Liebel Flarsheim Co | Resonance indicating and controlling device |
US2518129A (en) * | 1943-10-23 | 1950-08-08 | Honeywell Regulator Co | Control device |
US2558758A (en) * | 1944-01-22 | 1951-07-03 | Sperry Corp | Radio velocity indicator |
US2478311A (en) * | 1946-03-04 | 1949-08-09 | Marshall C Pease | Circuit for determining carrier frequencies of frequency modulated signals |
US2525780A (en) * | 1947-01-14 | 1950-10-17 | Charles E Dennis | Electrical frequency discriminator circuit |
US2499742A (en) * | 1948-06-11 | 1950-03-07 | Bell Telephone Labor Inc | Frequency modulation detector |
US2747146A (en) * | 1952-02-12 | 1956-05-22 | Cook Electric Co | Frequency enseitive control apparatus |
-
1936
- 1936-01-23 US US60420A patent/US2100394A/en not_active Expired - Lifetime
- 1936-09-18 GB GB25444/36A patent/GB481888A/en not_active Expired
- 1936-11-23 FR FR818511D patent/FR818511A/en not_active Expired
- 1936-12-31 NL NL47076D patent/NL47076C/xx active
-
1937
- 1937-01-18 DE DEI56904D patent/DE736084C/en not_active Expired
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2458943A1 (en) * | 1979-06-05 | 1981-01-02 | Victor Company Of Japan | FREQUENCY MODULATED SIGNAL DEMODULATION CIRCUIT |
Also Published As
Publication number | Publication date |
---|---|
US2100394A (en) | 1937-11-30 |
NL47076C (en) | 1939-06-15 |
DE736084C (en) | 1943-06-07 |
FR818511A (en) | 1937-09-30 |
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