Showing papers by "Hiroyoshi Ishikawa published in 2006"

Timing controller and timing control method

Abstract: A timing controller is disclosed that includes: an amplifier part configured to amplify a first input signal in accordance with a control voltage, the first input signal being one of a transmission signal and a signal of a fixed value; a detector part configured to detect envelope information from the output signal of the amplifier part; a controller part configured to determine a delay difference from the transmission signal and the envelope information and transmit a timing control signal based on the delay difference; and a delay corrector part configured to correct the delay of a second input signal in accordance with the timing control signal, the second input signal being one of the transmission signal and a signal of a fixed value. One of the first and second input signals employs the corresponding signal of the fixed value in the case of correcting the delay.

Peak suppression method, peak suppression apparatus and wireless transmission apparatus

Abstract: The present invention provides a peak suppression method, including a first step for detecting characteristic information of a peak part of a transmission signal; and a second step for changing a suppression method for the peak part based on the characteristic information.

Signal peak voltage suppression apparatus

Abstract: As in a conventional technology, a hard clipping process and a filtering process are performed on a transmission signal. An original transmission signal is subtracted from a signal on which the processes have been performed, and an inverse sign signal to the suppressed signal is retrieved. By giving a gain to the signal, and adding up to the original transmission signal, a peak voltage is suppressed. The gain can be a ratio of a difference signal between a hard clipped signal and an original transmission signal to a signal of suppression of a filtered signal from the original transmission signal, or a value determined by a simulation depending on the cutoff frequency of a low pass filter used in the filtering process.

Signal peak voltage suppressor

Abstract: PROBLEM TO BE SOLVED: To provide a signal peak voltage suppressor which is small and whose power consumption can be reduced without triggering deterioration of modulation accuracy or bit error rate. SOLUTION: Transmission signals are subjected to a hard clipping process and a filtering process in a conventional manner. The original transmission signals are deducted from the signals subjected to these processes and inversely signed signals corresponding to the suppressed ones are taken out. Suppression of the peak voltage is performed by giving a gain to the signals and adding them to the original transmission signals. A ratio between the decrease in the signals after hard clipping from the original transmission signals and the suppressed signals from the original signals after filtering is used or a value which is determined by simulation depending on a cut-off frequency of a low-pass filter used for the filtering process is used as the gain. COPYRIGHT: (C)2007,JPO&INPIT

Amplifier control device

Abstract: A bias control signal generation unit detects ON and OFF of a transmission signal input to an amplifier and having a property of a burst according to burst information. The bias control signal generation unit controls a bias voltage to be applied to an amplifier such that an idle current flowing through the amplifier can be flowing in a larger amount in a transmission OFF period, and can return to a normal level in a transmission ON period.

Delay controller and delay control method

Abstract: In an RF amplifier with input signal dependent power supply voltage control, a timing controller (432) is used to determine the delay of the main signal path (from node N via 411, 40 and 431 to 432) in a first step, while a fixed value from switch (421) is applied to the power supply control path, and to determine the delay of the power supply control path (from node N via 421, 422, 423, 40 and 431 to 432) in a second step, while the main amplifier (40) receives at its input a fixed value from switch (411). In a third step, a possible difference between these delays is corrected (423) by adjusting the delay of at least one of the two paths. After this calibration, the switches (411,421) couple the transmission signal to be amplified to both paths.

Timing adjusting method and timing adjusting apparatus

Abstract: A timing adjusting method detects a phase error between a main signal path from which a transmitting signal is obtained and a control signal path from which a voltage control signal is obtained, based on a to-be-amplified signal that is to be amplified and represents an amplitude or a power of the transmitting signal prior to amplification and a feedback signal that represents an amplitude or a power of the transmitting signal after the amplification, adjusts an amount of delay of at least one of the main signal path and the control signal path so as to mutually cancel the phase error, and amplifies the transmitting signal from the main signal path depending on the voltage control signal from the control signal path. The detecting the phase error may include detecting polarity transition points of a slope of a waveform of the to-be-amplified signal or the feedback signal, and measuring the phase error using the detected polarity transition points.

Timing adjusting device and timing adjusting method

Abstract: PROBLEM TO BE SOLVED: To time an input signal to an amplifier and a voltage control signal to each other in a transmitter which switches a source voltage of an amplifier for a linear transmitter according to the input signal level and outputs a less-distorted output signal with high amplification efficiency. SOLUTION: A timing adjusting device has a power amplifying means of amplifying a transmission signal from a main signal path according to the voltage control signal from a control signal path, a timing error detecting means of finding a phase difference between the main signal path and control signal path based upon a signal before the amplification which represents the amplitude or power of the transmission signal before the amplification and a feedback signal representing the amplitude or power of the signal after the amplification, and a means of adjusting a delay quantity of both or one of the main signal path and control signal path so that the phase difference is canceled. The timing error detecting means has a means of detecting a polarity change point of the gradient of the waveform of the signal before the amplification or feedback signal and a phase difference measuring means of measuring the phase difference by using the detected polarity change point. COPYRIGHT: (C)2007,JPO&INPIT

Multicarrier signal transmission apparatus and multicarrier signal transmission method

Abstract: A multicarrier signal transmission apparatus provided with a hard clip suppression unit for hard clipping a peak part of a multicarrier signal, a low pass filter for filtering the signal hard clipped by the hard clip suppression unit, and a peak suppression unit for suppressing the peak part of the signal after filtering by the low pass filter, the peak suppression unit provided with a peak detection unit for detecting a peak part of the filtered signal, a window function generation unit for generating a window function of an amplitude in accordance with a peak level of the peak part, and a peak suppressor for attenuating the peak part in accordance with the value of the window function.