Prev: Charge Conservation - Hint of the Day
Next: Make a limited XP account without losing settings?
From: Dirk Bruere at NeoPax on 20 Jul 2010 12:39
I want to drive a digital audio signal over CAT5.
I intend to use the DA103 transformer but need to check impedance matching.

Will 100R each end of the CAT5 be suitable?
Should the 100R on the transmitting end be before, or after, the xformer?

--
Dirk

http://www.transcendence.me.uk/ - Transcendence UK
http://www.blogtalkradio.com/onetribe - Occult Talk Show
From: JosephKK on 23 Jul 2010 00:09
On Tue, 20 Jul 2010 17:39:17 +0100, Dirk Bruere at NeoPax
<dirk.bruere(a)gmail.com> wrote:

>I want to drive a digital audio signal over CAT5.
>I intend to use the DA103 transformer but need to check impedance matching.
>
>Will 100R each end of the CAT5 be suitable?
>Should the 100R on the transmitting end be before, or after, the xformer?

The terminating restance should be at the far end of the cable. I
gotta ask though, in there any reasonable way that you could send the
signal digitally? like manchester encoded? The whole thing can work
much better that way.
From: Dirk Bruere at NeoPax on 23 Jul 2010 11:52
On 23/07/2010 05:09, JosephKK wrote:
> On Tue, 20 Jul 2010 17:39:17 +0100, Dirk Bruere at NeoPax
> <dirk.bruere(a)gmail.com> wrote:
>
>> I want to drive a digital audio signal over CAT5.
>> I intend to use the DA103 transformer but need to check impedance matching.
>>
>> Will 100R each end of the CAT5 be suitable?
>> Should the 100R on the transmitting end be before, or after, the xformer?
>
> The terminating restance should be at the far end of the cable. I
> gotta ask though, in there any reasonable way that you could send the
> signal digitally? like manchester encoded? The whole thing can work
> much better that way.

Forgot to add...
The input signal is standard SPDIF.
I'm going to bump it up to TTL level and use that to feed into a am26C31
line driver and then into the transformer. The other end is an SPFIF
receiver, so I have to do an impedance match (and voltage reduction to
around 1V).

--
Dirk

http://www.transcendence.me.uk/ - Transcendence UK
http://www.blogtalkradio.com/onetribe - Occult Talk Show
From: JosephKK on 24 Jul 2010 09:45
On Fri, 23 Jul 2010 16:52:36 +0100, Dirk Bruere at NeoPax
<dirk.bruere(a)gmail.com> wrote:

>On 23/07/2010 05:09, JosephKK wrote:
>> On Tue, 20 Jul 2010 17:39:17 +0100, Dirk Bruere at NeoPax
>> <dirk.bruere(a)gmail.com> wrote:
>>
>>> I want to drive a digital audio signal over CAT5.
>>> I intend to use the DA103 transformer but need to check impedance matching.
>>>
>>> Will 100R each end of the CAT5 be suitable?
>>> Should the 100R on the transmitting end be before, or after, the xformer?
>>
>> The terminating restance should be at the far end of the cable. I
>> gotta ask though, in there any reasonable way that you could send the
>> signal digitally? like manchester encoded? The whole thing can work
>> much better that way.
>
>Forgot to add...
>The input signal is standard SPDIF.
OK.
>I'm going to bump it up to TTL level and use that to feed into a am26C31
>line driver and then into the transformer. The other end is an SPFIF
>receiver, so I have to do an impedance match (and voltage reduction to
>around 1V).

Actually, i think all you really need is the impedance match (both
ends and let the voltage scale). Unless you are going a lot farther
than SPDIF is rated for, in which case the driver may be called for.
From: Dirk Bruere at NeoPax on 26 Jul 2010 19:34
On 24/07/2010 14:45, JosephKK wrote:
> On Fri, 23 Jul 2010 16:52:36 +0100, Dirk Bruere at NeoPax
> <dirk.bruere(a)gmail.com> wrote:
>
>> On 23/07/2010 05:09, JosephKK wrote:
>>> On Tue, 20 Jul 2010 17:39:17 +0100, Dirk Bruere at NeoPax
>>> <dirk.bruere(a)gmail.com> wrote:
>>>
>>>> I want to drive a digital audio signal over CAT5.
>>>> I intend to use the DA103 transformer but need to check impedance matching.
>>>>
>>>> Will 100R each end of the CAT5 be suitable?
>>>> Should the 100R on the transmitting end be before, or after, the xformer?
>>>
>>> The terminating restance should be at the far end of the cable. I
>>> gotta ask though, in there any reasonable way that you could send the
>>> signal digitally? like manchester encoded? The whole thing can work
>>> much better that way.
>>
>> Forgot to add...
>> The input signal is standard SPDIF.
> OK.
>> I'm going to bump it up to TTL level and use that to feed into a am26C31
>> line driver and then into the transformer. The other end is an SPFIF
>> receiver, so I have to do an impedance match (and voltage reduction to
>> around 1V).
>
> Actually, i think all you really need is the impedance match (both
> ends and let the voltage scale). Unless you are going a lot farther
> than SPDIF is rated for, in which case the driver may be called for.

The only worry is that the receiving chip is 3V3 and I do not want to
risk damaging it by feeding it some overvoltage. Can bad impedance match
bump up the voltage through reflections?

I checked the specs for the am26c31 and the output is around 3V (5V
Vcc), so after the xformer and resistors it will certainly be less.

--
Dirk

http://www.transcendence.me.uk/ - Transcendence UK
http://www.blogtalkradio.com/onetribe - Occult Talk Show
 |  Next  |  Last
Pages: 1 2 3
Prev: Charge Conservation - Hint of the Day
Next: Make a limited XP account without losing settings?