Abstract: The reverse rotation section phase-rotates received symbols in a direction opposite to the rotation direction on the transmitting side by an amount of phase rotation corresponding to each of a plurality of modulation schemes which are likely to be used on the transmitting side, the symbol decision section decides known symbols symbol by symbol in a training sequence section (known signal section), the error calculation section calculates decision errors, the comparison section compares the decided known symbols with a predetermined known symbol string corresponding to each of a plurality of modulation schemes which are likely to be used on the transmitting side in ascending order of the magnitude of errors and the modulation scheme decision section decides a modulation scheme to be used on the transmitting side according to the comparison result.

Abstract: A data receiving apparatus is constructed to make comparison of received signal strength of a plurality of receiving antennas by making use of timing of a sync word, which is not necessary for making synchronization acquisition, among a plurality of sync words contained in a subframe of a receiving signal, and then to select a receiving antenna of the highest received signal strength from among the plurality of receiving antennas, in accordance with a result of the comparison made before then.

Abstract: In an equalizer including a plurality of delay elements, a plurality of weighting elements and an adder, the impulse response of a signal transmission channel is estimated to selectively switch over a plurality of selector switches associated with the inputs and outputs of the respective delay elements, thereby selectively changing the combination of the delay elements and the weighting elements transmitting an input signal from the channel to the adder and also changing the combination of the adder and a delay element feeding back the output of the discriminator to the adder. Thus, the number of required taps of the equalizer can be reduced, so that the power consumption and size of the equalizer can be reduced.

Abstract: An apparatus and a method utilized in the field of time division multiplex digital communications or the like for detecting the place of burst signals. A transmitter transmits a carrier wave modulated by message data signals having a reference signal inserted between them, and a receiver receives the transmitted modulated carrier wave. In the receiver, the received modulated carrier wave is demodulated by both a sine wave and a cosine wave each having an angular frequency deviation .DELTA..omega. relative to the received carrier waved, the phase difference between the demodulated message data signals and the modulated reference signal is detected, the time-based change of the detected phase difference is approximated by a function of low order, the error between the phase of the received reference signal and that computed on the basis of the approximation function is computed, and a burst place detection signal is generated when the computed error is smaller than a predetermined threshold value.

Abstract: In an equalizer including a plurality of delay elements, a plurality of weighting elements and an adder, the impulse response of a signal transmission channel is estimated to selectively switch over a plurality of selector switches associated with the inputs and outputs of the respective delay elements, thereby selectively changing the combination of the delay elements and the weighting elements transmitting an input signal from the channel to the adder and also changing the combination of the adder and a delay element feeding back the output of the discriminator to the adder. Thus, the number of required taps of the equalizer can be reduced, so that the power consumption and size of the equalizer can be reduced.

Abstract: A data transmission apparatus with an improved error-rate characteristic after soft decision decoding by improving a decoder input such that, according to an embodiment, digital data such as voice data transmitted after being applied with coding and modulation are received, and are demodulated by a demodulator as a working mode thereof. A square mean value of errors is obtained by an error calculator on a demodulator output, and(1-e.sup.-2x/.sigma..spsp.2)/(1+e.sup.-2x/.sigma..spsp.2)is computed by a likelihood calculator and adopted as a decoder input.

Abstract: A data decoding device eliminates the need for encoding by a decoder for estimating an error rate and can estimate the error rate at a high precision even if an error is included. A square error sum is calculated by an error calculator based on an output of an equalizer. A estimated error rate is determined based on the error sum, a likelihood is determined based on the estimated error rate, and soft discrimination decoding is made based on the likelihood and the output of the equalizer.

Abstract: According to the present invention, a large compensation effect can be obtained in a small operation volume regardless of which one of a distortion due to a frequency selective fading and a distortion due to an interference of adjacent waves is ruling. In the present invention, a principal wave signal and signals of channels adjacent to both sides of said principal wave are taken out, and power of these signals is compared to select either one of the fractional interval equalizer and the linear decision feedback equalizer.

Abstract: A data receiving apparatus capable of correctly obtaining decoded data of a received signal even if the center frequency of the received signal has a frequency shift and the state of transmission line changes with time. The coefficient of an equalizer is calculated basing upon an error signal obtained from the received signal and a shift of the center frequency obtained from the error signal. The coefficient is renewed each time a new received signal is supplied.

Abstract: A data receiver which enhances a probability of frame synchronization even if a transmission line quality is bad detects a specific bit sequence in a received signal demodulated by a demodulator to deduce a transmission line quality by a line quality deducer. If the transmission line quality is so bad that a frame synchronization detector cannot detect the specific bit sequence, the specific bit sequence is detected from a received signal demodulated by an equalizer after the elimination of a transmission line distortion.

Abstract: The present invention relates to a frame synchronization method for digital mobile radio communication comprising generating a plurality of pulses having different phases on the basis of an asynchronous frame marker, and generating a synchronous frame marker on the basis of the pulses. In the method, a pulse having the same phase as that of the asynchronous frame marker, another pulse having its phase delayed by 1/2 of one clock period and another pulse having its phase delayed by one clock period are generated to be suitably selected.