IQ rate setting and acquisition time using 5641R

[atifyaqoob]

Hi,

I am doing some signal recording using the 5600 down converter and 5641 IF transceiver. I am having some strange timing issue with my signal acquisition. I am using an IQ rate of 1.5625 MSamples/sec and recording 2500 data blocks continuously and 6250 samples in one data block. With the said setting, I am actually recording 6250*2500=15625000 IQ Samples. The issue is that the acquisition time is supposed to be 10 seconds but it is taking 20 seconds time. If I change the number of data blocks, then the time is also changing but I am always having double of the expected time.

As the IQ rate is in Samples/sec so why it is taking double of the time. Any body can comment on this issue!

Thanks,

Atif

[atifyaqoob]

Hi,

Actually I am using the instrument driver interface programming. I am using external clock for the IF transceiver. By using Configure Ref Clk.vi, I am setting the clock source as Clk In and it is actually causing the problem for me. If I use the Onboard Clock, then there is no timing issue. Can some one from National Instruments advice me that how can I handle this issue with the instrument driver interface programming.

many thanks in advance!

/Atif