Patent ID: 8194718
Filing Date: 2012-06-05
Classification: H04B,H04L

Abstract:
1. A receiving apparatus that receives and processes a communication signal with frequency hopping among a plurality of frequency bands, said receiving apparatus comprising: a demodulator to demodulate a received signal; and a local signal generator to generate a local signal with a frequency corresponding to a frequency band of the received signal and output the local signal to the demodulator, the local signal generator performing a frequency switching of the local signal during a guard interval period of the received signal, wherein the demodulator is formed by a balance circuit, wherein the demodulator includes: a frequency converter to perform a frequency conversion by multiplying the received signal, which is converted into differential signals, by the local signal and obtain differential outputs; two capacitors, with one end of each of the two capacitors is respectively connected to one of two outputs of the differential outputs of the frequency converter: and a charge/discharge circuit to cause the two capacitors to perform a charge/discharge in synchronization with the frequency switching of the local signal so that a voltage difference between other ends of the two capacitors becomes a prescribed level, wherein the charge/discharge circuit causes the charge/discharge to be performed in synchronization with the frequency switching of the local signal so that voltages at the other ends of the two capacitors become essentially equal, wherein the charge/discharge circuit is placed for each of the two capacitors, wherein the charge/discharge circuit includes: two voltage sources, each connected to the other end of one of the two capacitor through a respective resistor; and a switch circuit to directly connect the two voltage sources to the other end of the respective capacitor by turning on in synchronization with the frequency switching of the local signal, and wherein the two voltage sources have a same voltage level.