{"id":1571,"date":"2023-06-17T14:11:22","date_gmt":"2023-06-17T19:11:22","guid":{"rendered":"https:\/\/paulcarbone.com\/blog\/?p=1571"},"modified":"2023-06-24T11:21:12","modified_gmt":"2023-06-24T16:21:12","slug":"tektronix-111-pulse-generator","status":"publish","type":"post","link":"https:\/\/paulcarbone.com\/blog\/tektronix-111-pulse-generator\/","title":{"rendered":"Tektronix 111 Pulse Generator"},"content":{"rendered":"\n
\"\"<\/figure>\n\n\n\n

This’ll be a quick one. The 111 is a pulse generator with ~ 500pS risetime. it has a pre-trigger output, which is adjustable from ~30nS to ~250nS. This makes it very easy to use an external trigger, and get the pulse centered on the screen. <\/p>\n\n\n\n

Mine had 2 problems:
1) the pre-trigger delay wasn’t adjustable
2) the rate wasn’t adjustable, being fixed at ~200kHz or so. <\/p>\n\n\n\n

Always check the rails first. The -15V line was down around -9V. I did a quick test of the Zener diode, which had to be done with a power supply, out of circuit. <\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

The multivibrator portion of the circuit was adjusting, but the avalanche section that generates the sharp pulse<\/s>* pre-trigger generator was oscillating in free-run, not taking it’s cue from that multivibrator. <\/p>\n\n\n\n

Next I decided to check Q40, which turned out to be bad, showing up on my chinesium tester as 2 diodes. <\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

I decided to just jam some basic bitch PNP transistor in there to see if it would work. To my surprise, it did! <\/p>\n\n\n\n

* Edit: Q40 is not running in avalanche, that’s Q84. It would have been very lucky<\/em> if some random transistor was capable of generating a sharp, predictable avalanche pulse.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Now I’ve got adjustable pre-triggering at 500pS, which has been useful for testing out some of my sampling plugins. <\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

<\/p>\n","protected":false},"excerpt":{"rendered":"

This’ll be a quick one. The 111 is a pulse generator with ~ 500pS risetime. it has a pre-trigger output, which is adjustable from ~30nS to ~250nS. This makes it very easy to use an external trigger, and get the … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[26],"tags":[72,27],"table_tags":[],"_links":{"self":[{"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/posts\/1571"}],"collection":[{"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/comments?post=1571"}],"version-history":[{"count":5,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/posts\/1571\/revisions"}],"predecessor-version":[{"id":1601,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/posts\/1571\/revisions\/1601"}],"wp:attachment":[{"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/media?parent=1571"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/categories?post=1571"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/tags?post=1571"},{"taxonomy":"table_tags","embeddable":true,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/table_tags?post=1571"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}