Digital electronics for ALMA

The IRAM Backend laboratory has been chosen to design and produce the ALMA antennas' digitizer clocks.

Inside each of the 64 Alma antennas the incoming cosmic signals will be converted to digital data. Every 250 picoseconds (which is 4 billion times a second), the antenna's digitizer issues a number, representing the cosmic signal. In order to preserve coherency between the different antennas, the antennas' digitizer clocks have to deliver the capture times for these numbers with extreme accuracy.

Mixing radio frequency and digital electronics, the IRAM Backend group designed a digitizer clock which is able to output pulses that can be shifted by 15 picoseconds steps, upon central computer command. 

For an image of the clock delivering 15 picosecond spaced steps, click here.

Digitizer clock synthesis block diagram