Digital signal receiver
A digital signal receiver includes a reference signal generator for generating a first reference signal, a base band transform circuit for converting a first high-frequency signal with digital modulation into a base band signal with using the first reference signal, a frequency divider to divide the first reference signal, a frequency multiplier to multiply a frequency of a signal output from the frequency divider, and a digital demodulator to demodulate a signal output from the base band transform circuit with using the signal output from the frequency multiplier as a reference signal. The digital signal receiver consumes a small power since a small current flows in the frequency multiplier.
1 . A digital signal receiver comprising:
a reference signal generator for generating a first reference signal;
a base band transform circuit for converting a first high-frequency signal with digital modulation into a base band signal with using the first reference signal;
a frequency divider to divide the first reference signal;
a frequency multiplier to multiply a frequency of a signal output from the frequency divider; and
a digital demodulator to demodulate a signal output from the base band transform circuit with using the signal output from the frequency multiplier as a reference signal.
2 . The digital signal receiver of claim 1 , further comprising a frequency converter for receiving a second high-frequency signal modulated by the digital signal and converting a frequency of the second high-frequency signal to generate the first high-frequency signal.
3 . The digital signal receiver of claim 2 , wherein the frequency converter converts the second high-frequency signal into the first high-frequency signal with using the first reference signal.
4 . The digital signal receiver of claim 1 , wherein the first high-frequency signal is modulated by the digital signal by Orthogonal Frequency Division Multiplexing system, and the digital demodulator comprises an Orthogonal Frequency Division Multiplexing demodulator.
5 . The digital signal receiver of claim 1 , wherein the base band transform circuit comprises an orthogonal base band transform circuit operable to convert the first high-frequency signal into a first base band signal and a second base band signal orthogonal each other and output the first base band signal and the second base band signal.
6 . The digital signal receiver of claim 5 , wherein the orthogonal base band transform circuit includes
a 90°-phase shifter for shifting a phase of the first reference signal by 90 degrees,
a first mixer for mixing the first reference signal with the first high-frequency signal to convert the first high-frequency signal into the first base band signal, and
a second mixer for mixing the second reference signal with the first high-frequency signal to convert the first high-frequency signal into the second base band signal.
7 . The digital signal receiver of claim 1 , further comprising a device including the frequency divider and at least one of the base band transform circuit and the frequency converter.
8 . The digital signal receiver of claim 1 , further comprising a device including the digital demodulator and the frequency multiplier.
9 . The digital signal receiver of claim 1 , further comprising a low-pass filter for receiving a signal output from the frequency divider and outputting a signal to the frequency multiplier.