[time-nuts] RS485/422/232 Chip

[Didier Juges]

> -----Original Message-----
> From: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] On Behalf Of Bruce Griffiths
> Sent: Saturday, April 26, 2008 8:51 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] RS485/422/232 Chip
> 
> 
> Any idea of the jitter of the Analog Devices transformer 
> coupled isolators?
> 
> Bruce
> 
Bruce,

That should be easy enough to check. I believe they use the 300MHz clock
gated, so the jitter is probably at least equal to the clock period, and
probably more if they use envelop detection. I have not come around to doing
that yet (all I know is that they have no problem getting my 9600 baud
serial data across :-) I will check with the scope first, then if it looks
good, I will put the 5370 on it.

The LTC part uses capacitive coupling instead of transformers, but they do
not say if they use an RF carrier, or simply on/off pulses. I could check
that one too.

I will let you know.

Didier 

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