Class AB amplifier and a distortion corrector therefor

• US 4,682,119 A
• Filed: 01/27/1986
• Issued: 07/21/1987
• Est. Priority Date: 01/25/1985
• Status: Expired due to Term

• Current Assignee: Thomson-CSF
• Original Assignee: Thomson -Csf
• Inventors: Michel, Jean
• Primary Examiner(s): Mullins, James B.
• Application Number:
  US06/822,834
• Time in Patent Office: 540 Days
• Field of Search: 330/149, 332/37 R, 328/162, 358/35, 358/184, 455/50
• US Class Current: 330/149
• CPC Class Codes: H03F 1/3217 in single ended push-pull amplifiers
• CPC Class Codes: H03F 1/3241 using predistortion circuits H03F1/3211, H03F1/3217 take precedence

Abstract

A class AB amplifier and its distortion corrector are provided for obtaining linear amplification, even for low input signal levels. For this, at low levels, the distortion corrector has a response Vs'"'"'=f(Ve'"'"') (with Ve'"'"' and Vs'"'"': input and output voltages of the corrector) whose representative curve has a concavity turned towards the increasing values of Vs'"'"' whereas, up to now, a prejudice born of an insufficiently precise study of class AB amplifiers led to an inverse curve for the response of the corrector.

Claims

1. A class AB amplifier including a distortion corrector, the corrector comprising a trough corrector, the quiescent current of the amplifier being chosen so that the characteristic Vs=f(Ve) of the amplifier, where Ve and Vs are respectively the input and output voltages of the amplifier has a monotonic variation drift,

and wherein the characteristic Vs'"'"'=f (Ve'"'"') of the trough corrector where Ve'"'"' and Vs'"'"' are respectively the input and output voltages of the trough corrector has a concavity which increases in absolute value of slope towards increasing absolute values of Vs'"'"'.

2. An amplifier and its distortion corrector as claimed in claim 1, wherein the amplifier operates at radio frequency and wherein the distortion corrector operates at intermediate frequency.