GB1368419A - Crystal controlled frequency discriminator - Google Patents
Crystal controlled frequency discriminatorInfo
- Publication number
- GB1368419A GB1368419A GB2771273A GB2771273A GB1368419A GB 1368419 A GB1368419 A GB 1368419A GB 2771273 A GB2771273 A GB 2771273A GB 2771273 A GB2771273 A GB 2771273A GB 1368419 A GB1368419 A GB 1368419A
- Authority
- GB
- United Kingdom
- Prior art keywords
- frequency
- demodulator
- well
- shift register
- output
- 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
- H03D3/18—Demodulation of angle-, frequency- or phase- modulated oscillations by detecting phase difference between two signals obtained from input signal by means of synchronous gating arrangements
- H03D3/20—Demodulation of angle-, frequency- or phase- modulated oscillations by detecting phase difference between two signals obtained from input signal by means of synchronous gating arrangements producing pulses whose amplitude or duration depends on phase difference
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
- H03D2200/00—Indexing scheme relating to details of demodulation or transference of modulation from one carrier to another covered by H03D
- H03D2200/0001—Circuit elements of demodulators
- H03D2200/0039—Exclusive OR logic circuits
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
Abstract
1368419 Frequency demodulator; FSK demodulator SINGER CO 11 June 1973 27712/73 Headings H3A and H4P A frequency demodulator comprises a shift register 18 responsive to a crystal controlled clock source 20, 22 for providing a constant delay to a frequency modulated input signal, a gate 28 coupled to receive the direct as well as the delayed input signal for producing constant energy output pulses whose mark to space ratio is dependent on the phase difference of the two applied signals. The constant delay is normally arranged to be “ the time period of the centre frequency of the incoming modulated signal (equivalent to a phase shift of 90 degrees) and is determined by the number of stages in the shift register 18 as well as by the clock frequency. In operation, the incoming modulated signal is limited at 12 and applied to an exclusive OR circuit 28 directly as well as via the shift register 18 which produces varying phase shift upon frequency deviations from the centre frequency. This results in output pulses from 28 having a mark to space ratio dependent on the frequency deviations from the centre frequency. These output pulses are integrated at 32 to obtain the demodulated output. The demodulator described above may be used as a FSK demodulator to obtain a two level output from integrator 32 which may be further applied to a differential amplifier 38 to obtain a two level output with well defined and sharp edges suitable for application to a computer or a teletype.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB2771273A GB1368419A (en) | 1973-06-11 | 1973-06-11 | Crystal controlled frequency discriminator |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB2771273A GB1368419A (en) | 1973-06-11 | 1973-06-11 | Crystal controlled frequency discriminator |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1368419A true GB1368419A (en) | 1974-09-25 |
Family
ID=10264072
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB2771273A Expired GB1368419A (en) | 1973-06-11 | 1973-06-11 | Crystal controlled frequency discriminator |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB1368419A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2144004A (en) * | 1983-07-25 | 1985-02-20 | Gen Electric | FM discriminator circuits |
CN114526691A (en) * | 2022-02-21 | 2022-05-24 | 上海电机学院 | Grid type double-pixel phase demodulation method for liquid crystal spatial light modulator |
-
1973
- 1973-06-11 GB GB2771273A patent/GB1368419A/en not_active Expired
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2144004A (en) * | 1983-07-25 | 1985-02-20 | Gen Electric | FM discriminator circuits |
CN114526691A (en) * | 2022-02-21 | 2022-05-24 | 上海电机学院 | Grid type double-pixel phase demodulation method for liquid crystal spatial light modulator |
CN114526691B (en) * | 2022-02-21 | 2024-03-15 | 上海电机学院 | Grid type double-pixel phase demodulation method for liquid crystal spatial light modulator |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PS | Patent sealed | ||
PCNP | Patent ceased through non-payment of renewal fee |