US 5,398,260 A · Method and apparatus for restoring multi level/phase modulation data

Abstract

A method and apparatus for receiving multi level/phase modulation data and restoring the received data to its original data state. The received data is demodulated and deinterleaved. The deinterleaved data is decoded in a Trellis decoder. Here, when the data to be deinterleaved is not synchronized, the deinterleaving sync is shifted, the deinterleaving operation is again repeated, thereby correcting .+-.180.degree. phase error. The multi level/phase decoder includes an axis exchanger for exchanging the I-axis data and the Q-axis with each other. Accordingly, when the sync is not matched even though the sync is shifted by one cycle in the deinterleaver, the axis exchange is performed in the axis exchanger. Then, the axis-exchanges data is deinterleaved and Trellis-decoded, to thereby correct .+-.90.degree. phase error.

Claims10

Dependent claims

A method for receiving multi level/phase modulation data and restoring the multi level/phase modulation data into original data, said method comprising the steps of:

receiving I-axis data and Q-axis data which is obtained by demodulating the received multi level/phase modulation data;
deinterleaving the I-axis data and the Q-axis data;
Viterbi-decoding the deinterleaved data and determining if the Viterbi-decoded data is synchronized;
shifting by a predetermined interval the data deinterleaving sync position during said deinterleaving step when the Viterbi-decoded data is not synchronized;
and
exchanging the I-axis data and the Q-axis data with each other when it is determined that the Viterbi-decoded data is not synchronized for a predetermined number of times.

3 more elements

An apparatus for receiving multi level/phase modulation data and restoring the multi level/phase modulation data into original data, said apparatus comprising:

input ports for receiving I-axis data and Q-axis data which is obtained by demodulating the received multi level/phase modulation data, respectively;
an axis exchanger portion connected to said input ports for receiving the I-axis data, the Q-axis data and a predetermined control signal and selectively exchanging the axes of the I-axis data and the Q-axis data according to said control signal;
deinterleaver means for deinterleaving the I-axis data and the Q-axis data which is outputted from the axis exchanger, respectively;
a Viterbi-decoding portion for decoding the deinterleaved data according to a Viterbi algorithm and outputting a predetermined out-of-sync signal when it is determined that the Viterbi-decoded data is synchronized as a result;
and
a sync detecting portion for detecting the out-of-sync signal outputted from the Viterbi-decoding portion to supply a sync adjustment control signal for shifting a data deinterleaving sync position to the deinterleaver and to supply said control signal for controlling axis exchange to the axis exchanger.

3 more elements

Dependencies are inferred from the claim text.

Method and apparatus for restoring multi level/phase modulation data

Life of this patent

Method and apparatus for restoring multi level/phase modulation data

Life of this patent

Abstract

Claims10