Receiving apparatus, and computer readable memory medium that stores a program

摘要

Suitable gain control is achieved at low cost.;In a receiving apparatus, an RF signal that is amplified by an RF amp is converted to an IF frequency by a frequency conversion unit and amplified by an IF amp, then the output signal from the IF amp that was converted to a digital signal by an ADC is inputted to a digital processing unit. The output from the ADC is then filtered to a desired frequency by a digital filter and inputted to the digital processing unit. In the digital processing unit the signal power before filtering by the digital filter and the signal power after filtering by the digital filter are measured, and the power difference is calculated. Based on the power difference, which indicates the ratio of unnecessary power, the digital processing unit controls the gain ratio of the RF amp and IF amp.

主权项

1. A receiving apparatus comprising:
a first amplifier that amplifies a received wave using high frequency; a frequency converter that performs frequency conversion on a signal output from the first amplifier from a frequency band of the first amplifier to a frequency band at a later stage; an analog filter that filters the signal that has been subjected to frequency conversion by the frequency converter; a second amplifier that amplifies the signal, which was filtered by the analog filter, using a demodulation frequency; a converter that converts the output signal from the second amplifier to a digital signal; a digital filter that filters the digital signal output from the converter to a desired frequency band; a demodulator that demodulates the digital signal that was filtered by the digital filter; and a digital circuit to which the digital signal output from the converter before being filtered by the digital filter and the digital signal that was output from the converter and then filtered by the digital filter are inputted; wherein the digital circuit comprises:
a power difference calculation unit that calculates a power difference between the digital signal output from the converter before being filtered by the digital filter and the digital signal that was output from the converter and then filtered by the digital filter; anda gain control unit that, based on at least the power difference that was calculated by the power difference calculation unit, controls a gain ratio of the first amplifier and the second amplifier, wherein the gain control unit (i) compares a threshold value that indicates a settable gain ratio with the power difference; (ii) performs control so that, when the power difference is greater than the threshold value, the gain ratio of the first amplifier is lowered; and (iii) performs control so that, when the power difference is less than the threshold value, the gain ratio of the first amplifier is raised.