Microdyne Corporation

John M Moore

Michael S Balbes

This disclosure relates to electronic devices, such as a television receiver, whose bandwidth is automatically reduced when the signal-to-noise ratio of the incoming signals becomes lower. Two circuits respectively sample the received video signals and the noise. The outputs of these two circuits feed a divider which divides one output by the other. A tuned filter (which follows an IF stage of the television receiver), which varies its bandwidth according to a control voltage fed to it receives the varying output voltage of said divider. The video and noise signals, which are fed to the divider, are both derived from the sync signal of the television receiver. Timing circuits control the operation of the system. One of these circuits distinguishes the sync signals from the equalizing pulses and eliminates the latter thereby reducing the error in the noise measurements. Another timing circuit eliminates signals, that occur while video-intelligence is occurring, from entering into the signal-to-noise ratio determination. The system will perform for television signals in which the baseband signals satisfy the following:

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Silver Spring, MD, United States of America

John M Moore