Station Beam Test

Purpose

This test is intended to test if the station beamformer is functioning as expected. The station beamformer is the firmware component that sums partial (16 antenna) beams from each TPM into full station (256 antenna) beams.

NOTE: This test operates on all TPMs in a given station.

NOTE: For the station beamformer and data acquisition to function correctly, the 40GbE interfaces on all TPMs must be working as well as the link to the CSP destination. The CSP destination must be configured to route traffic to the server running the tests. For all tests the simplest option is for the CSP and LMC destinations to be the same network interface, routing all traffic to the server running the tests.

NOTE: This test only supports a power of 2 TPMs (1, 2, 4, 8, 16..). If the test is executed with an incompatible number of TPMs, it will automatically be skipped.

Methodology

  1. In the TPM firmware, a data pattern is generated at the input of the station beamformer. This happens on all TPMs simultaneously. The contents of the data are the encoded course frequency channel number and frame number.

  2. The CSP scaling in the last TPM in the station is configured depending on the number of TPMs beamforming. The value is calculated in order to scale the beamform sum back to the original data pattern. For example, a station beam for channel 20 will contain 20. If this is beamformed through 4 TPMs, the result will be 80. Therefore the CSP scaling is set to divide by 4 to get the original 20.

  3. The embedded DDR test is started and so is the antenna buffer. This is to maximise the DDR memory usage so any conflicts will be detected.

  4. Software acquires the station beam packets and compares the contents of the packets to the packet headers. The channel number and frame number within the packet should match the channel and frame within the header.

Typical issues

Some typical issues and how they present are shown in the following table:

Presentation: No data is received. Test halts indefinitely waiting for SPEAD packets.

Issue: Network configuration issue. Check the MTU is set to 9000 on every switch, port, VLAN or NIC in the chain.