Re: clock unit

On 2013-05-14, at 14:32, HÁRSFALVI Levente wrote:
> 
> A couple of years ago, I was "forced" to use an A520 RF Modulator to
> connect an Amstrad CPC to a projector. (I was not sure whether the
> projector was to support the standard analog RGB signal I had, thus the
> ugly solution of hooking a pure analog RGB source to an RGB projector
> using composite video). After receiving absolutely no composite color
> first, I was very surprised to learn that the MC1377 in the A520 had a
> slightly hacky color subcarrier oscillator circuit, which relied on the
> presence of a master clock signal which is provided by the Amiga. This
> master clock (7.7xMHz) is derived from the Amiga master clock, which is
> (in turn) an even multiple of the dot clock of the Amiga. Thus, the
> resulting color subcarrier clock is in sync with the machine's dot
> clock, even though the color encoder has a separate color subcarrier
> crystal and oscillator circuit.
> 
> It would be interesting to know whether the SX utilizes similar tricks
> in order to provide sync'd dot and color clocks.

It seems that I will have to capture the schematic. Meaning - I shall have to disassemble one unit completely. It will have to wait a bit though.

-- 
SD!
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