in order to emulate PAL,is it as simple as using 1.773447MHz for the cpu's clock speed instead of 1.7897725MHz,as stated in yoshi's doc?

No, for several reasons:

1. The PAL CPU speed is 1.662607MHz (not 1.773447MHz - yoshi's doc is wrong), so sound emulation needs to be adjusted accordingly.
2. The PAL NES uses XTAL/16 for CPU speed and XTAL/5 for PPU speed (as opposed to XTAL/12 and XTAL/4 for NTSC), giving a slightly different CPU:PPU speed ratio - result: 106+9/16 cycles per scanline (instead of 113+2/3 cycles per scanline)
3. PAL has 312 scanlines per frame (70 scanlines of VBLANK); NTSC only has 262 (20 scanlines of VBLANK)


--
Quietust
P.S. If you don't get this note, let me know and I'll write you another.

thanks,didn't know there was that much to it.

For the fourth time -- then fix the doc, it's public-domain now, and it wasn't my information anyways (blame Mark Knibbs ;)).

-- jdc

A better suggestion would be for you to fix the document or tell people to delete it. Spreading misinformation isn't that good of a thing to do...

Given a choice between slightly inaccurate information and NO information, I'll take slightly inaccurate every time. The nestech doc is basically the ONLY comprehensive document of its kind -- nearly every other doc just refers to it for the parts it gets right.