The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 06, 1995
Filed:
Dec. 28, 1993
Tadahiko Maeda, Yokohama, JP;
Koji Iino, Yokohama, JP;
Shuichi Obayashi, Urayasu, JP;
Syuuichi Sekine, Urayasu, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
A two-stage power amplifier device for use in a digital hand-held radiophone includes a first and a second amplifier circuit. The first amplifier is an exciter-stage amplifier for receiving a high-frequency input signal corresponding to a modulation signal to generate an amplified signal at its output. The second amplifier is a final-stage amplifier connected to either the input signal or the output of the exciter amplifier. A detector circuit is connected to the exciter amplifier, for monitoring variations in a bias current to be fed to the exciter amplifier, and for generating a detection signal indicative of the current variation thus detected. A linearizer circuit is connected to the detector and the final-stage amplifier. The linearizer is responsive to the detection signal, for forcing a bias voltage given to the final-stage amplifier to vary in potential while causing the bias voltage to remain in a univocally determinable relationship with a waveform of said input signal, to thereby increase the linearity of the final-stage amplifier.