Measure on
the reader CD NAD512
Converter MASH:
CD reader NAD512 is equipped with a MASH converter. I made some
measurements which I show here.
Converter MASH is a DAC. It is supplied by the digital flow coming from the
read-out circuits. I jump this part, because that does not present much
interest for the moment.
This DAC delivers a signal with frequency and variable duty cycle as shows in the following photograph:
Photograph
Then the signal is filtered in several stage. NAD uses 2
operational amplifiers per channel to remove the numerical harmonics.
The second photograph is a zoom of the first.
Supply of the NAD.
NAD uses only one transformer for all electronics.
- the first photo show the signal after rectifying. It
is a basic circuit with the usual saw signal on a condensator.
- the second photo watch the signal after the regulator. There remain
imperfections at low frequency, which could be eliminated by more
condensator.
- the third photo show the supply on the operational amplifier. There are
still imperfections present.
Created : August 28, 2004.
Last update : 11 november 2007.
