An improved instantaneous frequency meter for use with a multi-trace CRO: re-examination of the principles involved

S. Obara, T. Nagai

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

The instantaneous frequency display of single unit discharges provides a useful measure of neuronal activities. Such a device must produce voltage outputs proportional to the reciprocal of each inter-spike interval by on-line computation of the hyperbola of V = a/t. Segment approximation of the required hyperbola can be made by a series of exponential functions which increase in time constants by a factor of m. Numerical analysis of a normalized function indicates possible error maxima of 3.4, 2.4 and 1.1% for m of 2, 1.8 and 1.5, respectively. This prediction is fully confirmed by the actual performance where m of 1.5 is adopted. The test circuit combines only readily available ICs and other components, to give a linear F-V conversion over a dynamic range of 4-600 Hz with error maxima of approximately 1%. The outputs are square pulses of approximately 1.5 ms in duration through the use of a flexible sample-hold circuit. Compared with that of earlier models, this display mode gives better photographic records with the base-line in simultaneous multi-trace display. Simple and systematic methods are described for designing a circuit to one's own specifications, and also for compensating for component variations.

Original languageEnglish
Pages (from-to)89-98
Number of pages10
JournalJournal of Neuroscience Methods
Volume7
Issue number1
DOIs
Publication statusPublished - 1983 Jan

Keywords

  • instantaneous frequency
  • nerve impulse
  • reciprocal time-interval
  • sample-hold
  • segment approximation

ASJC Scopus subject areas

  • Neuroscience(all)

Fingerprint Dive into the research topics of 'An improved instantaneous frequency meter for use with a multi-trace CRO: re-examination of the principles involved'. Together they form a unique fingerprint.

Cite this