AM-FM combined stereo receiver
First Claim
1. A radio having an FM mode and an AM mode and arranged for receiving FM-band stereo signals in the FM mode and AM-band stereo signals in the AM mode and having baseband detector means for providing in the FM mode a baseband FM signal, the baseband FM signal including arctangent distortion, and baseband detector means for providing in the AM mode a baseband AM stereo phase signal, the AM stereo phase signal including a phase term, the radio further having a single tangent function processor for removing the arctangent distortion in the FM mode and for processing the phase term from tan-1 ##EQU5## to provide ##EQU6## in the AM mode.
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Accused Products
Abstract
An improved AM-FM combined stereo receiver is provided having a single processor for removing, in the FM mode, arctangent distortion, and in the AM mode, to process the phase term from arctangent ##EQU1## to determine ##EQU2## Further, the radio includes a single discriminator circuit wherein, in the FM mode, the discriminator tank circuit is used to convert frequency deviation to baseband audio and, in the AM mode, the discriminator tank circuit is used as the frequency-determining element for the voltage controlled oscillator (VCO), the VCO being used to translate the intermediate frequency (IF) signal to baseband.
21 Citations
6 Claims
- 1. A radio having an FM mode and an AM mode and arranged for receiving FM-band stereo signals in the FM mode and AM-band stereo signals in the AM mode and having baseband detector means for providing in the FM mode a baseband FM signal, the baseband FM signal including arctangent distortion, and baseband detector means for providing in the AM mode a baseband AM stereo phase signal, the AM stereo phase signal including a phase term, the radio further having a single tangent function processor for removing the arctangent distortion in the FM mode and for processing the phase term from tan-1 ##EQU5## to provide ##EQU6## in the AM mode.
Specification