Subject: Re: [stella] I really need to buy a scope From: Adam Wozniak <adam@xxxxxxxxxxxxxxxx> Date: Wed, 11 May 2005 20:00:21 -0400 |
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Wed, 11 May 2005, Chris Wilkson wrote: > Despite all of this, the delay (pin 10) input is supposed to be a DC > voltage. If you actually measure it, it will look like a DC voltage > with some high frequency (~50 MHz per above) noise riding on it. > Plus any noise that comes from VCC. I don't think the DC component is the important part. If you look at the schematic, the delay line is connected to the gates of several transistors in the delay chain. I think the frequency of the AC component is the important bit. Adjusting the pot on the board changes the time constant of a simple RC oscillator which generates the delay signal. Each time the delay line gets high enough to trigger those transistors, the colorburst frequency is shifted down the delay chain. I really need a scope. - -- adam@xxxxxxxxxxxxxxxx http://cuddlepuddle.org/~adam KG6GZR http://cuddlepuddle.org/~adam/resume.html -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (GNU/Linux) iD8DBQFCgpwWyvXf5Z0z5zERAmpSAJ9KEyb0rQc5SiSdkK/zIoea84uTbQCcDcnY CPNZI0Bk2sAMipZmfGCW+lY= =VY4Q -----END PGP SIGNATURE----- Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://stella.biglist.com
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