Eiji Arita

A dynamically configurable multiformat PSK demodulator for digital HDTV using broadcasting-satellite

In Japan, a new digital broadcasting service using the broadcasting satellite (BS digital) starts in the year 2000. The Japanese BS digital system has one of three different modulation formats (binary phase shift keying (BPSK), quadrature PSK (QPSK), and 8PSK), dynamically selected according to transmission and multiplexing configuration control (TMCC) data transmitted with the audio and video data. The TMCC data also include the inner code (convolutional code) rate. Thus, a demodulator LSI that automatically controls the modulation format and inner code is required for consumer receivers. The poor group-delay characteristic and the inaccurate quadrature down conversion of the analog front-end are critical to demodulator design for low bit-error rate (BER). The authors describe an LSI which employs a flexible carrier-recovery system achieving dynamically configurable multi-format demodulation, and a clock phase compensator and carrier phase shifter cancelling the poor performance of the analog front-end circuit.

An advanced fast channel tracking method for automotive digital TV receiver

In this paper, an advanced fast channel tracking method is proposed for automotive DTV (digital television) receiver. The auto channel tracking function tunes an alternative broadcaster which belongs to affiliation group automatically, when channel condition is getting worse. Auto channel tracking is a practical approach to keep comfortable reception. The proposed method substantially improves the channel tracking speed. The advantage of the proposed method is confirmed by experiments.

Cross detection method and its improved effect in BER for DAB diversity receiver

Broadcasting receivers with receiving function for digital radio service have been developed recently in the world. Especially in these receivers, DAB is widely deployed as digital radio broadcasting standards in many countries caused by the simplified digital demodulation architecture on receiver equipment. Though in DAB system, DQPSK is specified as modulation scheme, it has a general problem of deteriorating symbol error rate compared to that of synchronous detection. This is caused that demodulation method for DQPSK must be operated by using both noised received signal and noised delayed signal. Therefore, we propose a new noise reduction method using space diversity for decreasing noise effect. This method generates criterion symbol simply by referring some received signals in each antenna element, and also calculate phase difference between received signal and past received signal on another antenna element with depending on the phase shift of criterion symbol. Then DAB diversity receiver can obtain the advantageous effect in BER improvement effect by combining both conventional detected signals and additional generated signals as mentioned above. In this paper, we show that our proposal scheme can achieve the improved effect of required Eb/N0 of 0.2-0.5 dB on BER=10-3, in spite of simple additional receiver equipment.

High resolution MUSE-NTSC converter

The frequency characteristic of a simplified interpolation algorithm of MUSE is analyzed. The result of the analysis is applied to a MUSE-NTSC conversion system to realize high resolution. The system also achieves a reduction in the amount of hardware because of the simplified algorithm. >