John Phillips wrote in message


"The Direct Stream DigitalT pulse train "looks" remarkably
like the analog waveform it represents. More pulses point
up as the wave goes positive and down as the wave goes negative."

- How do I "look" at a pulse train?

You actually don't because SACD is encrypted, but I have seen diagrams
which draw the analogue representation of the stream's 1s and 0s on a
page with a pen whose line width is a reasonable fraction of the maximum
data rate. It does seem to create a visual approximation of the original
signal's amplitude.

It's not encrypted. It's just a bitstream at 2.8Mb/s.
If you put the digital signal through a simple RC low pass filter
you get something very like the original analogue audio signal.

Roger.

In article , The Old
Fogey wrote:
John Phillips wrote in message


"The Direct Stream DigitalT pulse train "looks" remarkably
like the analog waveform it represents. More pulses point
up as the wave goes positive and down as the wave goes negative."

- How do I "look" at a pulse train?

You actually don't because SACD is encrypted, but I have seen diagrams
which draw the analogue representation of the stream's 1s and 0s on a
page with a pen whose line width is a reasonable fraction of the maximum
data rate. It does seem to create a visual approximation of the original
signal's amplitude.

It's not encrypted. It's just a bitstream at 2.8Mb/s.
If you put the digital signal through a simple RC low pass filter
you get something very like the original analogue audio signal.

I was under the impression you were never going to be allowed to see the
bitstream, through licensing conditions restricting SACD manufacturers
from exposing interfaces where digital copies could be taken. I thought
SACD was going to be like DVD-A in this respect. Have I got this wrong?

John
--
John Phillips

In article , The Old
Fogey wrote:
John Phillips wrote in message


"The Direct Stream DigitalT pulse train "looks" remarkably
like the analog waveform it represents. More pulses point
up as the wave goes positive and down as the wave goes negative."

- How do I "look" at a pulse train?

You actually don't because SACD is encrypted, but I have seen diagrams
which draw the analogue representation of the stream's 1s and 0s on a
page with a pen whose line width is a reasonable fraction of the maximum
data rate. It does seem to create a visual approximation of the original
signal's amplitude.

It's not encrypted. It's just a bitstream at 2.8Mb/s.
If you put the digital signal through a simple RC low pass filter
you get something very like the original analogue audio signal.

I was under the impression you were never going to be allowed to see the
bitstream, through licensing conditions restricting SACD manufacturers
from exposing interfaces where digital copies could be taken. I thought
SACD was going to be like DVD-A in this respect. Have I got this wrong?

John
--
John Phillips