US 4,484,143 AGranted

CCD Demodulator circuit

AssigneeRockwell International Corporation

InventorsBarry T. French, Michael J. McNutt

Life of this patent

Estimating the term…

Loading patent…

Abstract

A semiconductor integrated circuit using charged coupled device (CCD) technology for performing demodulation of time-varying signals which have been phase or amplitude modulated. The CCD circuit performs a sampling of the time-varying signal at a suitable sampling frequency depending upon the frequency of the phase or amplitude modulation of the carrier. The CCD device converts the sample into an equivalent charge packet which is used to control the control electrode of a field effect transistor in an amplifier circuit. The magnitude of the sample is representative of the amplitude of the carrier so that the output of the field effect transistor represents a demodulated signal. The circuit is a broad spectrum device, operable with a signal frequency from the audio into the gigaHertz (GHz) frequency range.

Claims3

Dependent claims

In a data transmission system for sending digital data between a transmitter and a receiver over a transmission link by a modulated carrier signal in which predetermined phase differences and predetermined amplitude levels are established during successive modulation periods representative of preselected data combinations, a demodulator at the receiver for detecting said phase differences and said amplitude levels to restore the digital data to its original format which comprises:

a carrier signal input for supplying said modulated carrier signal;
a reference signal input for supplying a reference frequency signal;
first switch means having an input connected to said carrier signal input and an output;
second switch means having an input connected to said reference signal input and an output;
a charge coupled circuit having first and second inputs respectively connected to the outputs of said first and second switch means, and an output;
said charge coupled circuit functioning to demodulate said modulated carrier signal;
timing means connected to and controlling said first and second switch means for providing, at the outputs of said first and second switch means, signals representing a predetermined combination of the carrier and reference signals to said charge coupled circuit at predetermined times;
and
processing means connected to the output of said charge coupled circit for calculating the phase difference between said carrier signal and said reference signal.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/448,570Filed 10 Dec 1982 · division
Priority: 29 Aug 1979
Granted: 20 Nov 1984
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

H03D 1/22
Demodulation of amplitude-modulated oscillations: homodyne or synchrodyne circuits
G11C 27/04
Electric analogue stores, e.g. for storing instantaneous values: shift registers
H03D 13/00
Circuits for comparing the phase or frequency of two mutually-independent oscillations
H10D 30/60
Field-effect transistors [FET]: insulated-gate field-effect transistors [IGFET]