On 08/16/2017 11:33 AM, Al Kossow via cctalk wrote: > > > On 8/16/17 11:20 AM, Tony Duell via cctalk wrote: > >> But I am not so sure about AGC. I've looked at the schematics for >> some 5.25" drives and I can find no AGC circuits. Nor on the Sony >> 3.5" full-height 600rpm drives. So I would not be at all surprised if >> there was no AGC on this Teac. > > I suspect so too. I was very surprised the subject was even mentioned on > that thread. The closest I've seen to it was a mention in the FD55 manual > that the ASIC could change the gain of the preamp from 100X to 200X > > Matsushita patent 4656533 has a good description of a 1.2 meg read channel
I honestly don't know. For example, https://www.google.com.pg/patents/EP0058253A2?cl=en describes an AGC approach for flexible discs. Certainly tape and hard disk drives employ AGC; it would seem to be logical that at least someone's drives do. Note that AGC may also be referred to as VGA (variable gain amplifier) and the like. --Chuck
