Kabushikikaisha Kenwood

Ryuichi Okazaki

Kenichi Shiraishi

Akihiro Horii

Shoichi Suzuki

Shoji Matsuda

Soichi Shinjo

Atsushi Shinoda

Toshiyuki Takegahara

Hiroyuki Nagasaka

A BS digital broadcast receiver having no 8PSK-demapper and a less number of delay circuits for Trellis encoding. A QPSK baseband signal based upon a reception signal point position of an absolute-phased baseband demodulation signal is Viterbi-decoded by a Viterbi-decoder . An output of the Viterbi-decoder is convolution-reencoded by a convolution encoder . Upper four bits of phase error data are searched from a phase error table for carrier reproduction in accordance with a phase difference between 0 degree and a phase of a phase error detection reception signal point position. The upper four bits are delayed by delay circuits to by a total sum of a time taken to Viterbi-decode and a time taken to convolution-encode. The delayed outputs are demapped by a demapped value conversion circuit A code TCD determined from the demapped output and convolution encode output is output as an MSB of a Trellis 8PSK decode output from an MSB code judging/error detecting circuit

BS digital broadcast receiver

An AM data multiplexing modulation apparatus for multiplexing a digital signal to an AM modulation signal without adversely affecting an AM sync detection output even if AM sync detection is performed. An AM modulator AM modulates a carrier having a frequency fc by an input signal, an orthogonal modulator 3 orthogonally modulates a carrier having a frequency (fc+f.alpha.) by a QPSK baseband digital signal generated by a QPSK baseband digital signal generator 2, a sign inverter and a complex conjugate unit change the sign of a signal having the same phase as a reference carrier of vector shift and corresponding to a dibit formed by the QPSK baseband digital signal generated by the QPSK baseband digital signal generator, another orthogonal modulator orthogonally modulates a carrier having a frequency (fc-f.alpha.) by an output of the complex conjugate unit, the outputs of the two orthogonal modulators are added by an adder, this addition result is added to the output of the AM modulator by another adder which outputs an AM data multiplexing modulation output.

AM data multiplexing modulation apparatus

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Machida, Japan

Ryuichi Okazaki