AnsweredAssumed Answered

AD9361 fast sample rate change

Question asked by obruendl on Apr 8, 2015

We need to quickly change between two different channel configurations.

ConfigA: Bandwidth 2.4 MHz, Sample Rate 16 MSPS

ConfigB: Bandwidth 1.2 MHz, Sample Rate 8 MSPS

All sampling rates are (AD, HB3, HB2, HB1, FIR) are doubled from ConfigB to ConfigA.

The downsampling ratio of the FIR is one for both configurations.

We use the no-OS API.


We are in FDD mode and we change RX and TX at the same time.


Currently use the following procedure to change the channel configuration:

1. Change TX RF bandwidth (14 ms)

2. Change RX RF bandwidth (15 ms)

3. Change sampling rates (20 ms)

4. Update RX FIR coefficients (4.5 ms)

5. Updating TX FIR coefficients (3 ms)


We need to optimized the time required as much as possible since it directly influences the limitation of the end product. Questions:

1. I guess reducing the time for the RF bandwidth change is not really possible, right? Is it somehow possible to change RX and RX bandwidth in parallel?

2. Is it anyhow possible to keep the sampling rates of AD, HB3, HB2 and HB1 constant and only update the FIR filter (ratio 1 for ConfigA, ratio 2 for ConfigB) to change the sampling rate? This would allow us to not have to run step 3 which would safe 20 ms.

3. Is it possible to re-configure RX and TX FIRs in parallel?