Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Tatsuto Oka

Hiroyuki Yoshikawa

Shunsuke Hirano

A transmitter apparatus capable of reducing the distortions of vector modulated waves. This apparatus includes variable coefficient filters () in a stage preceding an amplitude signal voltage generating part () and also includes variable coefficient filters () in a stage preceding a phase modulated wave generating part (). These variable coefficient filters (-) are used to perform a pulse shaping, thereby adjusting the delay between an amplitude component modulated signal (r(t)) and a phase component modulated signal (SC(t)) whereby a resolution, which is finer than the sampling period of a signal processing, can be used to adjust the delay time difference between the amplitude component modulated signal (r(t)) and the phase component modulated signal (SC(t)). As a result, the distortions of vector modulated waves (Srf(t)) can be reduced to a sufficiently small level.

Transmitter apparatus

Transmission apparatus capable of reducing distortion of the vector modulation wave that is the transmission output to a sufficiently small level is provided. An amplifying section () generates a vector modulation wave based on an amplitude component modulation signal and a phase modulation wave. A synchronous demodulating section () detects the vector modulation wave, generates a synchronous demodulation signal, and sends this to a band filtering section (). The band filtering section () extracts a signal of the frequency component of the distortion from a synchronous demodulation signal outputted by the synchronous demodulating section (). A controlling section () then refers to the distortion component signal extracted by the band filtering section (), controls a delay time adjusting section () in such a manner that the signal level of the distortion component becomes small, adjusts a delay time difference between the amplitude component modulation signal and the phase component modulation signal, and reduces distortion of the modulation wave.

Transmission apparatus, communication apparatus and mobile radio apparatus

A two-point frequency modulation apparatus is provided that reduces input timing difference and improves modulation accuracy. Two-point frequency modulation apparatushas: PLL circuit; frequency division ratio generatorthat generates the frequency division ratio in frequency dividerbased on first digital baseband signal Sand carrier signal; adderthat adds second digital baseband signal Sto the output signal of loop filter; a delay index calculator (filter coefficient calculator) that calculates the delay index based on the magnitude of change in the amplitude of the output signal of adder; and a delay adjuster (digital filter) that shifts the phase of one of first digital baseband signal Sand second digital baseband signal Saccording to the delay index so as to reduce the phase difference.

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Kanagawa, Japan

Tatsuto Oka