DigitalDownConverter — Interfaces

Input Stream

The pipeline consumes one SPEAD2 multicast stream in MPIFR_EDD_Packetizer:2 format. The stream description is provided via the input_data_streams configuration key.

Field	Value
Format	`MPIFR_EDD_Packetizer:2`
Default sample rate	4 Gsps
Default bit depth	8 bit
Default samples per heap	4096
SPEAD2 item: timestep	id 5632
SPEAD2 item: polarization	id 5633
SPEAD2 item: payload	id 5634

Output Streams

The pipeline publishes one SPEAD2 multicast stream per output channel in DigitalDownConverter:1 format.

DigitalDownConverter:1

Field	Value
format	`DigitalDownConverter:1`
description	`The DigitalDownConverter stream 1`
port	`1337`
bit_depth	`32`
sample_rate	`1000000`
samples_per_heap	`2048`

SPEAD2 Items

ID	Name	Shape	dtype
5632	timestamp	(6,)	>u1
5633	channel	(6,)	>u1
5634	polarization	(6,)	>u1
5635	data	()	<f

Channel Naming Convention

Output stream keys in output_data_streams follow the pattern:

polarization_<pol>_<channel>_lower
polarization_<pol>_<channel>_upper

where <pol> is the polarisation index and <channel> corresponds to the LO index in f_lo. Center frequencies are computed as f_lo[i] ± output_samplerate/4.

KATCP Interface

The pipeline exposes a standard EDD KATCP server. Key requests:

Request	Description
`?configure <json>`	Load a new configuration
`?capture-start`	Begin data capture
`?capture-stop`	Stop data capture
`?deconfigure`	Release resources
`?sensor-list`	List available sensors
`?sensor-value <name>`	Query a sensor