---
title: "Audio Frequency Counter Program for the Timex/Sinclair ZX81"
type: "article"
slug: "audio-frequency-counter-program-for-the-timex-sinclair-zx81"
url: "http://localhost/article/audio-frequency-counter-program-for-the-timex-sinclair-zx81/"
markdown_url: "http://localhost/article/audio-frequency-counter-program-for-the-timex-sinclair-zx81.md"
published_at: "2020-10-27T17:09:46+00:00"
modified_at: "2024-05-26T14:34:53+00:00"
featured_image:
  url: "http://localhost/wp-content/uploads/2022/04/20230809-041332.jpg"
excerpt: "This program will run with as little as 1K of RAM and will allow frequency measurements of up to 28,500 Hz. This is useful for tuning RTTY tone generators, electronic musical instruments, tone encoders, and for calibrating audio generators. The audio signal is fed to the computer's earphone jack, and the frequency is displayed to…"
category:
  - name: "SyncWare News"
    slug: "syncware-news"
    taxonomy: "category"
    url: "http://localhost/category/periodicals/syncware-news/"
post_tag:
  - name: "TS 1000"
    slug: "ts1000"
    taxonomy: "post_tag"
    url: "http://localhost/tag/ts1000/"
  - name: "Type-in program"
    slug: "type-in-program"
    taxonomy: "post_tag"
    url: "http://localhost/tag/type-in-program/"
  - name: "ZX81"
    slug: "zx81"
    taxonomy: "post_tag"
    url: "http://localhost/tag/zx81/"
model:
  - name: "Sinclair ZX81"
    slug: "zx81"
    taxonomy: "model"
    url: "http://localhost/model/zx81/"
  - name: "Timex/Sinclair 1000"
    slug: "ts-1000"
    taxonomy: "model"
    url: "http://localhost/model/ts-1000/"
indiv:
  - name: "Carol F. Milazzo (KP4MD)"
    slug: "carol-f-milazzo"
    taxonomy: "indiv"
    url: "http://localhost/indiv/carol-f-milazzo/"
publication: "SyncWare News"
publication_r:
  id: 10245
  title: "SyncWare News"
  type: "periodical"
  url: "http://localhost/periodical/syncware-news/"
authors: "Carol F. Milazzo"
volume: "3"
issue: "1"
issues_articles:
  - id: 38947
    title: "SyncWare News v3 n1"
    type: "issue"
    url: "http://localhost/issue/syncware-news-v3-n1/"
pages: "17-18"
pubdate: "September-October 1985"
archive_link: false
volumeissue: "v3n1"
---

# Audio Frequency Counter Program for the Timex/Sinclair ZX81

This program will run with as little as 1K of RAM and will allow frequency measurements of up to 28,500 Hz. This is useful for tuning RTTY tone generators, electronic musical instruments, tone encoders, and for calibrating audio generators. The audio signal is fed to the computer’s earphone jack, and the frequency is displayed to the nearest Hz on the screen. *Carol F. Milazzo was formerly Charles F. Milazzo.*