Blanker inhibit circuit
AssigneeMotorola, Inc.
InventorsLarry Richard Wright, Donald Charles Cohlman
Life of this patent
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Abstract
A radio receiver includes a blanker circuit for muting the receiver in response to interfering noise signals. The invention contemplates a transistor switch which, when biased to its nonconducting state, inhibits blanker action. The transistor is biased to nonconduction when the receiver provided automatic gain control (AGC) level is below the threshold voltage of the transistor. An adjustment is provided for controlling the AGC level at which blanker inhibit is introduced. Temperature compensating circuitry maintains inhibit action response at the threshold voltage with changes in ambient temperature.
Claims5
An AM radio receiver including:
- means for receiving radio frequency signals;
- tuner means for processing the received radio frequency signals and producing audio output signals in response thereto, the tuner means also producing an automatic gain control signal having a level representative of the magnitude of the received radio frequency signals;
- a blanker circuit for detecting noise pulses in the received radio frequency signals and blanking the tuner means in response thereto;
- and
- inhibit means for inactivating the blanker circuit responsive to the automatic gain control signal assuming a predetermined level corresponding to a minimum received radio frequency signal level,
- whereby when the received radio frequency signals exceed the minimum value the inhibit means inactivates the blanker circuit.
Dependencies are inferred from the claim text.