Path: utzoo!mnetor!uunet!tektronix!tekcrl!tekfdi!videovax!bill
From: bill@videovax.Tek.COM (William K. McFadden)
Newsgroups: sci.electronics
Subject: Re: Ideas for 2.048MHz osc.?
Message-ID: <4979@videovax.Tek.COM>
Date: 27 Apr 88 21:21:26 GMT
References: <550@hub.ucsb.edu>
Reply-To: bill@videovax.Tek.COM (William K. McFadden)
Organization: Tektronix Television Systems, Beaverton, Oregon
Lines: 39

In article <550@hub.ucsb.edu> grosen@amadeus.ucsb.edu (Mark D. Grosen) writes:
>Osciallator Question:
>
>I need to generate a 2.048MHz clock.  Anybody have a good idea on how to
>do this?  Are there any power of 2 oscillators out there?

If you get desperate, you could do what I do and synthesize it from a crystal
of a different frequency.  For example:

Take a 1 MHz crystal oscillator and divide the frequency down to 1 KHz using
three decade counters.  Feed this into the signal input of a 74HC4046 phase-
locked loop.  Take the VCO output of the PLL, divide it by 2048 with a 4040
CMOS counter and feed the output into the phase detector input on the 4046.
Now, assuming you picked the right components for the 4046, you should get
2.048 MHz out.  Hence:



  +------+        +------+        +------+
  | 1 MHz|        |divide|        |      |
  | OSC. |------->|  by  |------->| PLL  |-------+-------> 2.048 MHz output
  |      |        | 1000 |        |      |       |
  +------+        +------+        +------+       |
                                     ^           v
                                     |       +------+
                                     |       |divide|
                                     +-------|  by  |
                                             | 2048 |
                                             +------+




It should take no more than six cheap IC's to implement this frequency
synthesizer.
-- 
Bill McFadden    Tektronix, Inc.  P.O. Box 500  MS 58-639  Beaverton, OR  97077
UUCP: ...{hplabs,uw-beaver,decvax}!tektronix!videovax!bill
GTE: (503) 627-6920         "How can I prove I am not crazy to people who are?"