Radio receiving apparatus
AssigneeKabushiki Kaisha Kenwood
InventorTakashi Takeuchi
Life of this patent
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Abstract
In a radio receiving apparatus, an analog received signal is converted into a digital received signal. An unwanted wave in an adjacent channel band is rejected, that is adjacent to a passband for the digital received signal. The digital received signal with no unwanted wave is converted into a first demodulated signal. The first demodulated signal is converted into a second demodulated signal in analog form. A noise component is extracted from the first demodulated signal. The second demodulated signal is suppressed under squelch control when a squelch voltage that is a voltage of the noise component after rectification and smoothing becomes equal to or higher than a predetermined threshold level.
Claims7
A radio receiving apparatus comprising:
- an analog-to-digital converter configured to convert an analog received signal into a digital received signal;
- an adjacent channel rejection filter configured to reject an unwanted wave in an adjacent channel band that is adjacent to a passband for the digital received signal;
- a detector configured to detect the digital received signal for which the unwanted wave in the adjacent channel band is rejected, thus generating a first demodulated signal;
- a digital-to-analog converter configured to convert the first demodulated signal into a second demodulated signal in analog form;
- a noise bandpass filter to extract a noise component from the first demodulated signal;
- and
- a squelch controller configured to suppress the second demodulated signal when a squelch voltage that is a voltage of the noise component after rectification and smoothing becomes equal to or higher than a predetermined first threshold level.
Dependencies are inferred from the claim text.