[sebhc] Re: Cassette software tapes for H-8

Carroll Waddell carrollwaddell at sc.rr.com
Sun Aug 6 07:35:18 CDT 2006

Mark Garlanger wrote:

> Hi Steven,
>   If I remember correctly, Carroll was working on that, I thought he
> had mentioned something about some phase issues he was having with it.
> I don't remember seeing if he was successful (and I didn't find it in
> a quick search through my email).
> Mark
> On 8/5/06, Steven Parker <sp11 at hotmail.com> wrote:
>> >I don't know how much storage the archives are allowed, but if someone
>> >wants to make the recordings of the cassettes, and they are too big,
>> >I have web space that can be used to store them.
>> >>Would it work you captured the digitalized sound from the tape (with a
>> >>sound card), then recorded that sound file back to a new tape? If 
>> it does,
>> >>that would be a nice way to also archive tapes.
>> Seems like it would be reasonably simple to convert the tape image files
>> into wav files on demand, so we'd just need to archive the utility along
>> with the tape images we already have, and then you could make tapes from
>> your pc sound card.
>> I remember this coming up before, maybe there is such a utility around
>> already?   If not, I could put one together when I get a chance (but 
>> it may
>> take a llittle while for me to get to it).
>> The other question .. does anyone have tapes not yet in the archive 
>> to add?
>> -- Steven
>> -- 
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> -- 
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I haven't had any time to work on it very much. (Been remodeling a house)
The cassette audio output is held at a MARK level. (Zero) This is 2400 
Hz. If you listen to the audio out, this is what you hear. To output a 
bit (One) the output goes to a SPACE. This is 1200 Hz. Because the 
cassette interface is running at 1200 bps, this is exactly 2 cycles of 
audio for MARK (ZERO) and 1 cycle of audio for a SPACE (ONE).
The shifting of each serial bit in the USART is done on the zero 
crossing of the audio signal. That is, the beginning of each data bit 
time occurs when the audio signal is crossing zero volts.
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