Browse Prior Art Database

Frequency Identifier

IP.com Disclosure Number: IPCOM000095845D
Original Publication Date: 1964-Aug-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 25K

Publishing Venue

IBM

Related People

Kivel, D: AUTHOR

Abstract

This plural frequency determining apparatus can identify the unknown frequency of a plurality of discrete signals supplied to it.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 87% of the total text.

Page 1 of 2

Frequency Identifier

This plural frequency determining apparatus can identify the unknown frequency of a plurality of discrete signals supplied to it.

The apparatus has an input amplifying circuit for accepting the sine wave signal with unknown frequency, a phase detector and free running multivibrator arrangement and a counter. After amplification and reshaping, the signal is applied to the phase detector which provides outputs in the form of short DC pulses. An output is provided for each of the four 90 degree phase regions of the input sine wave so that any particular phase of the signal can be detected. However, in the normal operation of the apparatus, the detector provides only a single pulse output for each frequency cycle of the wave being measured.

The first phase detector output pulse triggers the multivibrator and the second pulse inhibits it. Between the triggering and inhibition of the multivibrator, oscillation occurs at a known frequency. These oscillations are counted in the counter. The total count in the counter at the end of oscillation is then proportional to the frequency of the input signal.

Any combination of phase detector outputs can be employed to initiate and to terminate the counting as long as the counter output for the various input frequencies is unique. When the operation of the multivibrator is inhibited by the second output pulse from the phase detector, the input to the phase detector is degated. Before the beginning of another...