KR970068362A - Receiver in quadrature amplitude modulation (QAM) - Google Patents

Abstract

The present invention relates to a Quadrature Amplitude Modulation (QAM) scheme in a side and a demodulation system. In the QAM system, a carrier recovery unit includes an excellent filter and an odd filter, that is, two Since the filter performs the same operation using one filter, the number of taps of the filter is reduced to half compared with the conventional filter. If the same number of taps is used, the number of symbols can be doubled, thereby ensuring robustness against timing errors Also, the symbol equalizer and the half symbol period can be selectively used in the channel equalizer, so that the equalizing operation is performed using the data of the half symbol period according to the region or the channel state, or the delay time of the ghost is long In the region, the equalization operation is performed by using the data of the symbol period, so that the same number of taps can be adaptively processed according to the situation .

Description

Receiver in quadrature amplitude modulation (QAM)

Since this is a trivial issue, I did not include the contents of the text.

FIG. 3 is a block diagram of a receiving apparatus of the QAM system of the present invention. FIG. FIG. 4 is a block diagram of a conventional carrier recovery unit and a carrier recovery unit according to the present invention. FIG. 4 illustrates a conventional configuration, and FIG. 4 illustrates a configuration of a carrier recovery unit using the multi- Degree.

Claims (4)

A carrier recovery unit for separating the converted digital signal into an excellent signal and a radix signal, filtering the separated excellent signal and odd signal by alternately using an outer filter and an odd filter, and then combining the filtered outer signal and the radix signal, And a channel equalizer for alternately multiplying the output signal sequence of the carrier recovery unit with the real part and the imaginary part of the equalizer tap coefficient by the real and imaginary parts of the signal every clock and outputting it to the error correcting part. Modulation type receiving device. 2. The apparatus of claim 1, wherein the carrier recovery unit comprises: separating means for sequentially switching the input signal and separating the input signal into an excellent signal and a radix signal; an even filter for filtering the separated excellent signal with an even tap coefficient to generate a real signal; A quadrature filter for generating a quadrature signal by filtering the odd signal with an odd tap coefficient and a multiplexer for combining the real part and the imaginary part while alternating the generated real part and imaginary part signal, . 3. The apparatus of claim 1 or 2, wherein the channel equalizer comprises: a demultiplexer for downsampling to separate the superior signal sequence and the odd signal sequence of the carrier recovery unit output signal; and a demultiplexer for separating the signal streams separated from the demultiplexer into odd- And outputs the resultant signal to an error correction unit. 2. The receiver of claim 1, wherein the channel equalizer filters the output signal sequence of the carrier recovery unit through an even-numbered alternating peak filter in a symbol period according to a selection signal, and then filters the output signal sequence through an odd- . ※ Note: It is disclosed by the contents of the first application.