Re: 10Mhz under frequency in 184 Time-Mark Generator
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Don't measure the frequency at the xtal - you will pull it down a load.
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Measure at the output of the 1st gain stage (collector of Q94). David -----Original Message-----
From: [email protected] <[email protected]> On Behalf Of n4buq Sent: 07 December 2021 16:30 To: tekscopes <[email protected]> Subject: Re: [TekScopes] 10Mhz under frequency in 184 Time-Mark Generator At cold start, with 0.1us selected, the output checked 9.9981MHz. After about a 90 minute warmup, the crystal can is warm to the touch, cycle time is much longer, and the output still checks 9.9981MHz. I was going on memory that the output frequency was 9.999x and that's incorrect. I'll have to check the components as well as the interaction of L9. I think I adjusted that for uniformity of the markers but I don't think I tried checking to see whether I can reach a compromise between L9 and C8 to get good results for both frequency and marker uniformity. Thanks, Barry - N4BUQ |
David C. Partridge