James S Matson

US Patent:

45150214, May 7, 1985

Filed:

Jul 29, 1983

Appl. No.:

6/518738

Inventors:

David R. Wallace - Milton MA
James M. Korba - Woburn MA
James E. Matson - Brookline MA
Lawrence C. Lynnworth - Waltham MA

Assignee:

Panametrics, Inc. - Waltham MA

International Classification:

G01F 166

US Classification:

7386127

Abstract:

An intervalometer for determining the transit time of an ultrasonic energy pulse through a fluid medium employs an automatic gain control amplifier circuit for amplitude stabilizing the electrical signal derived at a receiving transducer. The automatic gain control circuit tracks both a rapidly increasing and a rapidly decreasing signal amplitude. In various embodiments, synchronous switching can be employed in conjunction with a single amplifier and a plurality of storage elements to rapidly scan a plurality of signal paths and for providing automatic gain control capability on each path. The intervalometer further has a "slipped cycle" capability for accurately determining arrival time when is is known that the signal pulse will be within a certain range of times. In addition, the relative time difference between two arriving signal pulses can be accurately determined using this method so long as the range of time difference is sufficiently small. The intervalometer also provides for bad data rejection based upon limits applied to either transit time or signal amplitude.