Send a command to the noise-cal power-meter.

Arguments:

PowerMeterCommand command

The type of command to send to the power meter.

Example 1:

The following example tells the power meter to reset to its power-on defaults.

  power_meter reset

Example 2:

The following example tells the power meter to perform a zero calibration.

  power_meter zero

Note that with the current power meter, while the zero-calibration process only takes between 15 seconds and a minute, it apparently takes much longer than that for the power meter measurements to settle down. The noise-cal task waits for a minute after starting a zero calibration before resuming its periodic readout of the measured power.

Example 3:

The following example tells the power meter to take a new power reading and record it in the noise.power archive register. This is only useful during testing, because usually the power meter is automatically read out at the rate set by the noise_readout_interval command.

  power_meter read

Context:

The noise-calibration system uses a dedicated gpib power-meter to measure the power output of its noise-generator. The power_meter command allows one to send simple commands to it. More complex commands can alternatively be sent with the gpib_send command (the GPIB address of the power meter is currently 13). See the power meter manual for details about the commands that are available.