FM composite signal processor
OwnerStephen J. Hemphillinventor
Life of this patent
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Abstract
A signal processor for amplitude and frequency limiting of a multiplex FM composite signal is described. To maximize the amount of available bandwidth and minimize the generated distortion, the disclosed signal processor employs multiple low-distortion amplifying and clipping subsystems. The subsystems include a stereophonic pilot signal protection circuit which protects the 19 khz pilot signal from the composite FM signal processing, an adjustable limiting circuit, and an adjustable dual low-pass filter/overshoot compensation circuit.
Claims24
A signal processor for use in preparation of a modulated signal to be broadcast comprising:
- a modulated signal;
- and,
- a clipping amplifier comprising:
- a first low-pass filter, having a first transfer function, receiving the modulated signal;
- a first overshoot compensator removing any modulation above a predetermined maximum modulation created by said first low-pass filter.
In a signal processor preparing a complex signal to be broadcast comprising, a circuit for protecting a pilot signal in a complex signal comprising:
- separating means for separating out the pilot signal;
- inverting means, receiving the pilot signal from said separating means, for reversing the phase of the pilot signal;
- a summing circuit combining the complex signal with the output of said inverting means to remove the pilot signal from the complex signal;
- processing means for processing the output from said summing circuit;
- restoring means for restoring the pilot signal with the output of the processing means.
In a signal processor preparing a modulated signal to be broadcast comprising, a circuit for limiting the modulation of a modulated signal comprising:
- a clipper amplifier receiving the modulated signal, said clipper operating between a predetermined high voltage and a predetermined low voltage;
- adjusting means adjusting the predetermined high voltage and the predetermined low voltage.
Dependencies are inferred from the claim text.