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. 12, 1984
Filed:
Aug. 17, 1981
David R Welland, Boston, MA (US);
DBX, Inc., Newton, MA (US);
Abstract
The invention relates to an improved voltage control amplifier of the type comprising a gain cell. The gain cell is of the type that includes at least one log transistor for each polarity of input signal and at least one antilog transistor for each log transistor, means for algebraically summing a control signal with the log signal provided by each log transistor and means for providing a symmetry adjust signal to the base of a selected transistor of the cell so that the cell provides substantially the same gain for each polarity of input signal when the control signal level is set for zero. The improvement comprises means for generating a correction signal as a function of the control signal level so as to substantially correct for differences between the early effects exhibited by said transistors as said control signal varies and means for applying the correction signal to the base of one the transistors.