PEAK HOLDING CIRCUIT

• US 3,777,263 A
• Filed: 02/17/1972
• Issued: 12/04/1973
• Est. Priority Date: 02/17/1972
• Status: Expired due to Term

• Current Assignee: Rule Industries Incorporated (ITT, Inc.)
• Original Assignee: Harvey L. Pastan, Robert R. Perron
• Inventors: Perron, Robert R., Pastan, Harvey L.
• Primary Examiner(s): Rolinec, Rudolph V.
• Assistant Examiner(s): Karlsen, Ernest F.
• Application Number:
  US05/227,174
• Time in Patent Office: 656 Days
• Field of Search: 324/13P,13R,99D,161,163,158MG 73/189
• US Class Current: 324/103.00P
• CPC Class Codes: G01P 3/489 Digital circuits therefor
• CPC Class Codes: G01P 3/56 for comparing two speeds
• CPC Class Codes: G01R 19/04 Measuring peak values or amplitude or envelope of ac or of pulses
• CPC Class Codes: H03M 1/48 Servo-type converters

Abstract

A peak holding circuit is provided wherein an analog voltage from a tachometer is converted to and stored as a digital value and the digital value is converted back to an analog voltage and compared continuously with the tachometer output and corrected when the digital value falls below that of said output. A practical application of the circuit is described wherein the peak value of an anemometer is stored for indefinite lengths of time.

Claims

1. A device for indicating selectively the instantaneous value of a tachometer output and a peak value of said tachometer output comprising in combination:

a. a tachometer providing a source of variable voltage, said voltage being proportional to the speed at which the tachometer is driven, b. a differential amplifier having one input connected to the output of said tachometer, c. an AND gate having one input connected to the output of said differential amplifier and a second input connected to a clock circuit providing a series of pulses, d. a binary counter and storage device connected to the output of said AND gate, e. a digital to analog conversion network connected to said binary counter whereby the binary count is converted to an analog signal, f. means for applying said analog signal to the second input of said differential amplifier as a feedback voltage whereby said differential amplifier will cause said AND gate to open whenever a voltage difference exists between the inputs to said differential amplifier, g. a meter in said circuit having switching means connected thereto whereby said meter can be connected directly to said tachometer output to indicate the instantaneous value of said tachometer output and switched to a second position into the feedback circuit whereby said meter will read the stored feedback voltage in said circuit to indicate the peak value of tachometer output.