Insert a given attenuation into the signal path of one or more channels.

Arguments:

Receivers receivers

The set of receivers to target.

Bands bands

The set of frequency bands to target.

Attenuation attenuation

The attenuation to insert into the specified channels.

Example 1:

The following example inserts the maximum programmable attenuation into the signal path of every channel.

 attenuate all, all, 31

Example 2:

The next example inserts 10db of attenuation into all channels who's signals originate from receiver 4.

 attenuate rx4, all, 10

Context:

The CBI has 13 receivers (rx0..rx12) who's 10GHz bandpasses are split into 10 bands (band0..band9) by a channelizer. The resulting 130 signal paths are refered to as channels. Every channel contains a programmable attenuator for setting the input power to the corresponding correlator input. The amount of attenuation needed by each channel depends on the sensitivity of the various components in the signal path and the brightness of the source. For bright planets more attenuation will be needed than when observing the CMB. Normally this attenuation should be set by using the tp command to request a given input power level, but it can also be set explicitly through the attenuate command.

Note that all of the attenuators are set to maximum attenuation when the control system starts.