Patent ID: 6259895
Filing Date: 2001-07-10
Classification: H04B

Abstract:
A transmitter-receiver that performs transmission and reception by selecting any of a plurality of equally set channels, comprising:an oscillation means for oscillating a signal at a certain frequency;a first frequency conversion means for getting a received radio-frequency signal an output signal of said oscillation means to convert the received radio-frequency signal to a first intermediate frequency signal;a first frequency division means for dividing the signal frequency of said oscillation means by a factor of N1;a second frequency division means for dividing the signal frequency of said oscillation means by a factor of N2;a second frequency conversion means for getting said first intermediate frequency signal and the output signal of said first frequency division means to output a second intermediate frequency signal;a demodulation means for demodulating said second intermediate frequency signal;a first frequency conversion means for transmission for getting the output signal of said first frequency division means and the output signal of said second frequency division means to output intermediate frequency signal for transmission; anda second frequency conversion means for transmission for getting the output signal of said oscillation means and the output signal of said first frequency conversion means for transmission to output a radio-frequency signal for transmission;wherein the frequency division number N1 of said first frequency division means and the frequency of the output signal of said oscillation means are predetermined so that a change in frequency of the output signal of said first frequency division means due to a change in said frequency division number N1 by a predetermined number is the same as said channel interval and this frequency division number causes said second intermediate frequency signal to be at a predetermined frequency, and wherein the frequency division number N2 of said second frequency division means is predetermined so that said radio-frequency signal for transmission is at a predetermined frequency.