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:
Jul. 27, 1976
Filed:
Sep. 04, 1974
Stephen Michael Bench, Lake Zurich, IL (US);
B-Cubed Engineering, Inc., Elgin, IL (US);
Abstract
The disclosed circuit provides a wideband, wide-range logarithmic responding voltmeter particularly suitable for use as a transducer analyzer. The circuit includes an input for receiving a given A.C. input signal which can vary within a 100 db dynamic range. The input signal is coupled to a buffer amplifier the output of which is capacitively coupled to a logarithmic converter. The converter includes an operational amplifier and provides an A.C. output signal which is proportional to the logarithm of its A.C. input signal. The open loop gain of the operational amplifier is utilized to provide the A.C. output signal. The output signal of the converter is capacitively coupled to a precision AC/DC converter which rectifies and filters the output signal to provide a D.C. output voltage the level of which is, therefore, also proportional to the logarithm of the given A.C. input signal within its 100 db range. The D.C. output voltage is coupled to utilization means such as a logarithmically calibrated chart recorder or meter. The precision AD/DC converter also includes a zero-adjustment for nulling any offsets in its circuit and any residual noise at the output of the logarithmic converter. Accordingly, with no input signal applied to the disclosed circuit the output recorder and/or meter stably read exactly zero ('0').