Understanding DTM example

RE: Understanding DTM example

Håkon Alseth — Mon, 29 Apr 2019 07:52:07 GMT

[quote user="eyalasko"][/quote]

If I understand correctly - packet received correctly is a packet where the packet address received correctly even if the payload has errors?

Sorry, forgot to mention the CRC checking. There's a 3 byte CRC attached to the end of the payload which is checked in firmware, and it will only tag the packet as "good" if the CRC matches with the payload content.

[quote user="eyalasko"]Is there a way to extract the received packet and verify the payload in software for better PER calculation?[/quote]

No, DTM does not include this possibility, as it should already be done on the device-under-test (DUT) side.

Kind regards,

Håkon

RE: Understanding DTM example

eyalasko — Sun, 28 Apr 2019 08:19:56 GMT

Thanks for the super-fast response.

If I understand correctly - packet received correctly is a packet where the packet address received correctly even if the payload has errors?

Is there a way to extract the received packet and verify the payload in software for better PER calculation?

Thanks again.

RE: Understanding DTM example

Håkon Alseth — Tue, 23 Apr 2019 10:30:28 GMT

Hi,

[quote user=""]How fast does the transmitter test sends out test packets ?[/quote]

This depends on the packet size. It varies from 625 us to 2500 us, in 625 us steps. 0 to 37 bytes payload length gives 625 us frame.

See Vol 6, part F, chapter 4.1.6 for details on the length of a frame, as there's a formula for calculating this there.

[quote user=""]Do the packets number reported in the packet response events reflect the true number of good packet received?
if so, how come that the number is not consistent. I get relatively large numbers even for very short receiver test (see screen caps)[/quote]

Yes, it gives back the overall packets it received. This will differ based on how long the test has been running, so you can use that time to calculate how many packets you expected to receive vs. what you actual received.

[quote user=""]How can I calculate the PER as I don't know how many packets were transmitted?[/quote]

See the above.

[quote user=""]Strangely, many received packets are reported even if transmitter and receiver's test parameters are not matching... [/quote]

The receiver has a certain address that it expects to receive packets on (0x71764129 in little endian), and regardless of the payload type, it shall receive the data, provided that your radio PHY is in order.

Kind regards,

Håkon