FW: RK05 question - test-drb@ccmp.vtda.org

13 Jul 2004

Isn't the track index pulse == the one pulse that is fed to the PLL
phase comparator?  That pulse is used to synchronize the oscillator
that must run at 12 (or 16) times the frequency between 2 sector
pulses to generate the (missing) sector pulses ....
or am I mistaken here?

- Henk, PA8PDP.

...
  -----Original Message-----
 From: cctalk-bounces(a)classiccmp.org
 [mailto:cctalk-bounces@classiccmp.org]On Behalf Of Paul Koning
 Sent: dinsdag 13 juli 2004 15:59
 To: cctalk(a)classiccmp.org
 Subject: Re: FW: RK05 question

 >>>> "Fred" == Fred N van
Kempen &lt;waltje(a)pdp11.nl&gt; writes:  
  Fred> On Tue, 13 Jul 2004, Paul Koning wrote:
  David> the "home" slit and synthesize the individual sectors. Never
  David> tried this with an RK05 [heck havent touched one of them in
  David> over 25 years!], but I have used this technique to synchronize
  David> otgher items.....
 >  I suppose that's possible.  One way to
do it would be to build a
> PLL that's locked to the start of track pulse, and derive a 12x or
> 16x sector clock from that.  Or, analogously, you could use a PLL
> to derive a 16 sector clock from the 12 sector clock (multiple by
> 4/3rd, not hard with a PLL).  That's probably a good solution...  
  Fred> Hm, and then ignore the "real" sector pulses and feeding the
  Fred> drive electronics the output of the PLL?  Smart, that should
  Fred> work, assuming one can format the packs given this "sector
  Fred> clock".

 Yes, that's what I had in mind -- hook the optical sensor to the PLL,
 feed the PLL output to where the sensor used to go.  The one obvious
 tricky part is to generate the track index pulse, because it isn't
 equally spaced along with the sector pulses.

  Fred> Would these then be called hard- or soft-sectored? :)

 Firm-sectored?  :-)

 	paul