Matsushita Electric Industrial Co., Ltd.

Youichi Morinaga

Hiroaki Kosugi

Hisashi Adachi

Kaoru Ishida

Hiroshi Iwai

Toshio Ishizaki

Toru Matsuura

Toshifumi Nakatani

Hiroshi Takahashi

Hideaki Nakakubo

Shunsuke Hirano

Naoki Yuda

Takashi Enoki

Tomoki Uwano

Toshio Obara

Takeshi Miura

Tsutomu Matsumura

Atsushi Sasaki

Ikuo Ohta

Hiroyuki Itokawa

Tooru Sakuragawa

When the radio circuit apparatus is transmitting, the output signal of the first local oscillator,is inputted to the transmitted frequency converter,as well as to the frequency divider,, and then the output signal of the frequency divider,is inputted to the modulator,. The modulator,modulates the output signal of the frequency divider,with a base band signal. The output signal of the modulator,is inputted to the transmitted frequency converter,to be converted to the frequency of a transmitted signal by the output signal of the first local oscillator,When the radio circuit apparatus is receiving, the output signal of the low noise amplifier,is inputted to the first frequency converter,to be converted to the first intermediate frequency by the output signal of the first local oscillator,The output signal of the filter,is inputted to the second frequency converter circuit,to be converted to the second intermediate frequency by the output signal of the second local oscillator,Thereby, unnecessary components for transmission can be easily lowered to make it possible to miniaturize the radio circuit apparatus.

Radio circuit apparatus and radio communication equipment

A power amplifier has an input signal splitting part for splitting the input signal into two output signals each having equal power and phase difference of 180 degrees with respect to each other. A first signal on-off selection part for switching conduction of one of the output signals. A first amplifying part for amplifying the signal from the first signal on-off selection part. A second signal on-off selection part for switching conduction of the signal outputted from the first amplifying part. A second amplifying part for amplifying the other of the output signals from the input signal splitting part. An output signal combining part for providing a phase difference of 180 degrees between the output of the second signal on-off selection part and the output of the second amplifying part and combining them. A bias on-off part for switching on and off at least the first amplifying part, wherein, when the output level is high, the first and second signal on-off selection parts are turned on and, at the same time, the first and second amplifying parts are turned on by the bias on-off part, so that push-pull operation is performed, and when the output level is low, the first and second signal on-off selection parts are turned off and the first amplifying part is turned off by the bias on-off part and the second amplifying part performs single-ended operation.

Power amplifier

Disclosed is a transmitter for switching and transmitting signals of plural frequency bands. For example, the signals of two frequency bands are switched and transmitted. For the transmission in a first frequency band, of transistors 104, 105 are turned off, whereby a power amplifying transistor 102 is matched by an input wide band matching circuit 101 and an output main matching circuit 103, so that the high efficiency linear amplification is accomplished. For the transmission in a second frequency band, the transistor 104 is turned on while the transistor 105 is turned off, whereby the power amplifying transistor 102 is matched by a capacitance 108 as well as the input wide band matching circuit 101 and the output main matching circuit 103, so that the high efficiency linear amplification is accomplished. An external switch for switching the matching circuits is thus unnecessary.

Mobile telephone transmitter with internal auxiliary matching circuit

A transceiver circuit with a heterodyne receiver circuit is provided. Output signals of first and second local oscillator 103, 104 are mixed by a local frequency converter 105. An output signal of the converter 105 passes a filter 106 and inputs a modulator 111 of a transmitter circuit 101 as well as a first frequency converter 122 of a receiver circuit 102. The second local oscillator 104 comprises a frequency synthesizer whose output signal varies for a transmission or a receiving mode. The output signal of the second local oscillator 104 also inputs the second frequency converter 124 of the receiving mode. A reference frequency of the second local oscillator 104 is set higher than a frequency step between communication channels so that a quick switching of the frequency is performed. Thus, the transceiver circuit of this invention is suitable for a compact size and hardly generates unwanted spurious components at transmission mode.

Transceiver circuits for TDMA system with variable frequency second

A frequency synthesizer that can switch an output frequency fast and generates little spurious output is provided. This frequency synthesizer comprises a phase locked loop including a voltage-controlled oscillator, a high frequency divider, a phase frequency comparator and a low-pass filter. The divisor controller circuit supplies a divisor that varies cyclically to the high frequency divider for a fractional dividing operation. When switching the output frequency, a passing bandwidth of the low-pass filter is enlarged to widen a loop bandwidth of the phase locking loop for fast switching. After switching, the passing bandwidth of the low-pass filter is reduced to narrow the loop bandwidth for reduction of a spurious output, at the timing when a predetermined period has passed for the switched output frequency to stabilize substantially.

Fast frequency switching synthesizer

An antenna switching device of the present invention includes: a transmitting terminal for receiving a transmitting signal; a first antenna terminal connected to a first antenna; a second antenna terminal connected to a second antenna; a receiving terminal for outputting receiving signals received at the first antenna terminal and the second antenna terminal; a selecting unit for selecting one mode among a first mode for outputting a signal corresponding to the transmitting signal to the first antenna terminal, a second mode for outputting the receiving signal received at the first antenna to the receiving terminal, and a third mode for outputting the receiving signal received at the second antenna to the receiving terminal.

Antenna diversity switching device with switching circuits between the

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Yokohama, Japan

Youichi Morinaga