GB1410530A - Modulating and demodulating circuits - Google Patents

Modulating and demodulating circuits

Info

Publication number
GB1410530A
GB1410530A GB5474772A GB5474772A GB1410530A GB 1410530 A GB1410530 A GB 1410530A GB 5474772 A GB5474772 A GB 5474772A GB 5474772 A GB5474772 A GB 5474772A GB 1410530 A GB1410530 A GB 1410530A
Authority
GB
United Kingdom
Prior art keywords
input
output
potential
capacitor
circuits
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
Application number
GB5474772A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
PROCESS PERIPHERALS Ltd
Original Assignee
PROCESS PERIPHERALS Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by PROCESS PERIPHERALS Ltd filed Critical PROCESS PERIPHERALS Ltd
Priority to GB5474772A priority Critical patent/GB1410530A/en
Publication of GB1410530A publication Critical patent/GB1410530A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K7/00—Modulating pulses with a continuously-variable modulating signal
    • H03K7/06—Frequency or rate modulation, i.e. PFM or PRM
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K9/00—Demodulating pulses which have been modulated with a continuously-variable signal
    • H03K9/06—Demodulating pulses which have been modulated with a continuously-variable signal of frequency- or rate-modulated pulses

Landscapes

  • Amplitude Modulation (AREA)

Abstract

1410530 Pulse modulation circuits; frequency demodulators PROCESS PERIPHERALS Ltd 27 Nov 1973 [27 Nov 1972] 54747/72 Headings H4L and H3A Pulse period modulation and demodulation circuits are disclosed which are suitable for the recording and playback of television waveforms. Modulator.-Input signal Vin, Fig. 1, is arranged to be positive at terminal A with respect to grounded terminal B and terminal A is connected to the non-inverting inputs of differential amplifiers A1, A2. Capacitors C1, C2 are connected to line B and provided with constant current charging circuits T1, R1 and T2, R2 respectively, which are controlled by inverting gates G3, G4 in accordance with the periodmodulated output signal derived from a bistable G1, G2 receiving the outputs of amplifiers A1, A2. When an inhibiting signal is applied to G2 its output is positive and the output of G1 is at ground potential so that G3 is in the "off" state and capacitor C1 commences to charge. When the potential on C1 exceeds the input potential Vin, the output of A1 reverses and if the inhibiting potential is now removed, the output of A1 will set G1 to "off" and G2 to "on" to reverse the state of gates G3, G4 so that C1 begins to discharge and C2 to charge. When the potential on C2 just exceeds Vin the negative output of A2 will cause the action to reverse again so that half periods of oscillation which are linearly proportional to the input voltage are derived. Demodulator.-The period-modulated input is supplied in opposite polarities via inverting gates G11; G12, to capacitors C11, C12 provided with constant current charging circuits R11, T11, and R12, T12 respectively. The capacitors are connected via switching circuits S11, S12, controlled to operate in synchronism with polarity changes of the input signal, to a common amplifier A1 and a low pass filter removes the carrier component. When the input is of one polarity, C1 is charged linearly by its constant current device and the amplitude it reaches at the instant the input signal changes state is proportional to the duration of the charge. When the input states reverse, capacitor C2 charges in a similar manner, each capacitor being discharged in the other half-cycle by gates G11, G12. The potentials on each capacitor are switched in turn, during their charging periods, to the amplifier A11.
GB5474772A 1972-11-27 1972-11-27 Modulating and demodulating circuits Expired GB1410530A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB5474772A GB1410530A (en) 1972-11-27 1972-11-27 Modulating and demodulating circuits

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB5474772A GB1410530A (en) 1972-11-27 1972-11-27 Modulating and demodulating circuits

Publications (1)

Publication Number Publication Date
GB1410530A true GB1410530A (en) 1975-10-15

Family

ID=10471950

Family Applications (1)

Application Number Title Priority Date Filing Date
GB5474772A Expired GB1410530A (en) 1972-11-27 1972-11-27 Modulating and demodulating circuits

Country Status (1)

Country Link
GB (1) GB1410530A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3413143A1 (en) * 1984-04-07 1985-10-17 Grundig E.M.V. Elektro-Mechanische Versuchsanstalt Max Grundig holländ. Stiftung & Co KG, 8510 Fürth FM modulator
EP1381158A2 (en) * 2002-07-02 2004-01-14 STMicroelectronics S.r.l. Frequency/signal converter and switching regulator employing said converter

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3413143A1 (en) * 1984-04-07 1985-10-17 Grundig E.M.V. Elektro-Mechanische Versuchsanstalt Max Grundig holländ. Stiftung & Co KG, 8510 Fürth FM modulator
EP1381158A2 (en) * 2002-07-02 2004-01-14 STMicroelectronics S.r.l. Frequency/signal converter and switching regulator employing said converter
EP1381158A3 (en) * 2002-07-02 2004-02-04 STMicroelectronics S.r.l. Frequency/signal converter and switching regulator employing said converter
US6924632B2 (en) 2002-07-02 2005-08-02 Stmicroelectronics S.R.L. Frequency/signal converter and switching regulator having such a converter

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Legal Events

Date Code Title Description
PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee