Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: notesfiles - hp 1.2 08/01/83; site hp-pcd.UUCP
Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxt!houxm!ihnp4!pesnta!hplabs!hp-pcd!raan
From: raan@hp-pcd.UUCP (raan)
Newsgroups: net.video
Subject: Re: counters on VCRS
Message-ID: <20600018@hpcvry.UUCP>
Date: Mon, 24-Jun-85 22:26:00 EDT
Article-I.D.: hpcvry.20600018
Posted: Mon Jun 24 22:26:00 1985
Date-Received: Sun, 30-Jun-85 02:21:06 EDT
References: <433@zinfande.UUCP>
Organization: Hewlett-Packard - Corvallis, OR
Lines: 41
Nf-ID: #R:zinfande:-43300:hpcvry:20600018:000:1623
Nf-From: hpcvry!raan    Jun 24 18:26:00 1985

>> I recently purchased a Fisher stereo VHS VCR.  In general, I am very happy
>> with its performance, but I've noticed the record-length timer is non-linear.

>> In other words, a half-hour recording at the begining of the tape is not
>> equivalent in counter-units to a half-hour recording at the middle or end
>> of the tape. (as the tape rolls, the counter units are longer with respect
>> to time).

>> Is this normal?

Yes.

There are two (at least) basic methods for generating the tape counter reading.
If your unit has a mechanical counter (like an odometer on a car) then you
probably have method 1.  If it is an electronic counter, then it may use
either method, but your observation would indicate that it uses method 1.

1)  The counter counts the revolutions of one of the tape reels.  If it is
the take-up reel, then as more tape winds on to the reel (causing it to
thicken), each turn has a larger circumference and hence takes more tape
(and therefore a longer time).  If it is counting the source reel, then
the same affect takes place in reverse and the times will get shorter as
the tape progresses.

2)  The counter counts the timing signals that are recorded on the tape.
These would be consistant as the tape progresses, so you would not see any
variation.  This type of counter usually displays its count in terms of
time elapsed, which is very useful.  Most of the newer Sony machines do
this.



---  Raan Young (hp-pcd!raan)

     ~~~~~~~~~~~~~~~
     hplabs    ---->\
     harpo     ----> \
               ---->  >--!hp-pcd!raan
     microsoft ----> /
     textronix ---->/
     ~~~~~~~~~~~~~~~