Re: Help: How to transmit IRG B code?

Aug 14, 2003 0 Replies


Hi,


>
> I have a project I'm working on, for personal use, and need some
> help. I have several time-code generators(Datum) that have IRG-B
> inputs, and outputs on the rear. Now they are connected via
> coax output to input. I would like to get rid of the
> cable and transmit the code wireless. I'm thinking
> of using RF modules. It is more involved than first thought,
> however. The IRG-B code is a 1000Hz carier. Any help
> would be appreciated.
>

Mix the 1000 Hz signal with your desired RF carrier frequency and amplify. In practice the mixer will give sum and difference frequency outputs (plus, for the purists, a lot of other products). If your carrier frequency is 1 MHz the output signal will consist of 999 kHz,


1000 kHz and 1001 kHz (assuming an unbalanced mixer). Separating these signals would require a filter but is not really practical without using a crystal filter. So the normal technique is to mix to an intermediate frequency - perhaps 50 kHz where it is much easier to filter out the unwanted frequency - then mix again to your final output frequency.

The above is the old way of doing this - there are modern techniques that achieve the same using I & Q signals through an A to D.


HTH - but I suspect the answer will be not much!


Jim Backus OS/2 user bona fide replies to jimb-thecirclethingy-jita-dp-demon-dp-co-dp-uk or remove "NOT" from address remove dashes and make the obvious substitutions for valid email address

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