Amplifiers – Hum or noise or distortion bucking introduced into signal...
Reexamination Certificate
2000-02-22
2001-09-18
Pascal, Robert (Department: 2817)
Amplifiers
Hum or noise or distortion bucking introduced into signal...
C330S12400D, C375S297000
Reexamination Certificate
active
06292055
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an electronic apparatus comprising a power amplifier formed by:
an output stage having a non-linear amplification characteristic,
a correction assembly for compensating for the non-linearities of said characteristic.
The invention also relates to an amplifier suitable for such an apparatus.
The invention finds applications in mobile radiotelephony devices for which the requirements of the transmitter are demanding as regards the purity of the spectrum of the transmitted signals. This necessitates, inter alia, that the output amplifier working at high frequency has a very good amplification linearity.
Patent document of Japan published under no. 08125554 describes such an amplifier. To obtain a proper linearity, various means are provided forming a rather complex structure.
SUMMARY OF THE INVENTION
The present invention proposes an apparatus of the type defined in the opening paragraph that presents a simpler structure.
Therefore, such an apparatus is characterized in that the correction assembly comprises:
a low-power preamplifier of the same type as said power stage,
a combining device for combining the input signals with the output signals of said preamplifier to counteract the non-linearities of said characteristics.
The idea of the invention is that when the amplifiers are integrated on the same chip, the characteristics are similar whatever the power of the amplifiers, this power in fact depending on the surface occupied by the output transistors.
REFERENCES:
patent: 5043673 (1991-08-01), Suematsu et al.
patent: 5151664 (1992-09-01), Suematsu et al.
patent: 5774018 (1998-06-01), Gianfortune et al.
patent: 6037837 (2000-03-01), Miyaji et al.
Rodrigo Cordeiro Tupynamba et al: “Mesfet Nonlinearities Applied to Predistortion Linearizer Design” International Microwave Symposium Digest (MTT-S), Albuquerque, Jun. 1-5, 1992, vol. 2, pp. 955-957 Figure 2.
Patent Abstract of Japan: Publication No.: 08125554 A, Date of Publication: May 17, 1996.
Choe Henry
Pascal Robert
Slobod Jack D.
U.S. Philips Corporation
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