Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Electric Corporation

Masakazu Morita

Masayuki Ishida

Kenichi Taura

Tadatoshi Ohkubo

Masahiro Tsujishita

Jun Ido

Mitsuru Takeuchi

Tadashi Sakaguchi

A delay profile generating circuitgenerates a delay profile signal. Concerning the delay profile signal, a ghost decision circuitmakes a decision as to the presence or absence of ghosts that will appear during traveling of a mobile vehicle in response to a transmission mode signal fed from a changeover switch. The delay profile signal and the decision signal about the presence/absence of the ghosts are delivered to a window control circuitvia an accumulator. The window control circuitsets and controls the FFT window position of an FFT circuitin response to a guard correlation signal fed from a guard correlation signal generating circuitand a signal fed from the accumulator

Digital broadcasting receiving apparatus with channel estimation function

A digital audio broadcast receiver detects frame synchronization signals, measures the pulse widths of and intervals between the detected frame synchronization signals, and stores this information in a memory, together with a history of counts of frame synchronization signals, and stores this information in a memory, together with a history of counts of frame synchronization signals of certain widths detected at certain intervals. This information is retained in the memory until frame synchronization is acquired, as determined from the stored count values, enabling frame synchronization to be acquired quickly despite the false detection of frame synchronization signals due to noise.

Digital audio broadcast receiver acquiring frame synchronization quickly in the presence of noise

A digital audio broadcasting receiver comprises a phase error detector for detecting a phase error from data from a differential demodulator, an average value processing unit for determining the average value of phase errors, a memory for storing the phase errors of the carriers outputted from the phase error detector, and a phase error correcting unit which excludes a phase error whose sign is opposite to that of the average value among the phase errors stored in the memory, and determined the average value of phase errors again, thereby making it possible to obtain a phase error signal which is less affected by leakage from other carriers.

Digital audio broadcasting receiver

To control the oscillation frequency of a local oscillator, a digital broadcast receiver demodulates a phase-reference symbol contained in an orthogonal frequency-division multiplexed broadcast signal to obtain an array of complex values, selects several sets of values from the array, multiplies each selected value by the complex conjugate of a value offset by N positions in the array (where N is a fixed integer that may be equal to zero), averages the results in each set, takes differences between the average values, or between sums of these average values, thereby obtains two difference values, and calculates a frequency offset from the difference values. Each set of values is taken from positions at which the known reference-symbol values satisfy certain conditions in relation to the known values at adjacent positions.

Digital broadcast receiver

A digital audio broadcast receiver searches for a receivable digital audio broadcast signal by first searching for a signal, having at least a predetermined power level, in which frame synchronization symbols can be detected. This stage of the search is made by searching a known frequency grid, or by scanning in steps approximately equal to the bandwidth of the digital audio broadcast signal. After frame synchronization symbols have been detected, the receiver attempts to find the center frequency of the received signal, changing the receiving frequency in steps less than the bandwidth of the digital audio broadcast signal, if necessary. A prompt indication that a receivable digital audio broadcast signal has been found is given when frame synchronization symbols are detected, or when the center frequency is found.

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Tokyo, Japan

Masakazu Morita