Noise Diodes (J.Quick)

The HP1000 controls the calibration Noise Diodes through a 3:8 multiplexed relay based driver circuit. In the NCCS independent control of up to 16 noise diodes is required. Furthermore all noise diodes must be capable of being continuously toggled by some external reference signal.

The following solution was proposed :

• Each noise diode should be driven by a circuit capable of being switched into one of three states: ON, OFF or MODULATING, producing a TTL level command output.
• Each noise diode circuit when MODULATING can be switched to track any one of up to eight external reference inputs under computer control.
• Each noise diode circuit should include a state detector driven by a feedback signal originating as close to the actual noise diode as possible.
• Up to eight of these circuits should be consolidated into one board with a common multiplexed computer interface capable of being driven by a SDIO unit, ie. supporting full remote configuration and control.
• Each board should interface through a noise diode specific adapter that produces the necessary drive voltages/currents and returns a direct TTL state indicator.

Tasks completed:

DESIGN NEW NOISE DIODE CONTROL CIRCUIT,

ADD SUPPORT FOR NOISE DIODES INTO SDIO DEVICE SERVER,

Tasks still to be done :

BUILD THREE INTEGRATED EIGHT-WAY NOISE DIODE CONTROLLERS.

DESIGN AND BUILD CALIBRATION NOISE DIODE DRIVER INTERFACE.

Note: The same circuitry can be used to control Dicke Switches as well merely by adapting the final driver interface suitably.