AY

In AY there are three generators that continuously produce a meander
with a given frequency (R0/1, R0/2, R0/3).
There is also a noise generator that continuously produces a noise
signal with a given frequency (R6). Noise differs from a meander in that
in a meander after each clock cycle the level changes to the opposite
and in noise to a random one.
The last generator is an envelope generator which, at a given frequency
(R11/12), reduces/increases/does not touch the volume of the envelope. The type
which is set (R13).
Next, all these signals go to the mixer. If the channel tone bit (R7b0,1,2)
is reset, then the square wave for this channel is skipped, if the noise bit
(R7b3,4,5) is reset, then the noise signal is skipped. If both bits are clear
then 1 is skipped. The tone and noise signals are mixed by AND.
After this, the line of each channel is set to the specified amplitude
(R8/R9/R10). If bit 4 of the amplitude register is turned on, the
current envelope amplitude is used.
If noise and tone are masked for a channel, then the channel outputs the current
amplitude level.
From all this it follows that if noise and tone are masked and envelope mode is turned on
for a channel, then the output will be an envelope signal.
Is that correct? Please check on a real AY for reliability.
To do this, issue the commands:
OUT 65533,7: OUT 49149,255: REM mask the channels
OUT 65533,8: OUT 49149,16: REMturn on the envelope mode
OUT 65533,13: OUT 49149,10: REM turn on the periodic envelope
if I'm right, you will hear the sound

Sincerely
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