Faster retune possible

[eroom1966]

Hi All,

I have a requirement for a faster retune in synchronous, direct sampling mode - which involves

1. change of frequency
2. change of sample rate

I am looking at creating a modified version of rtl_sdr, nothing else changes, and there are only 2 datasets I am interested in switching between Mode 1: FreqA, SampleRateA Mode 2: FreqB, SampleRateB When performing the switch I send the data down 1 of 2 different fifo's which have decoders listening for data.

By making calls to the API routines under a high performance Linux OS macine, it seems that the total time to call both routines in succession, is in the order of 100ms This is quite long, and I noticed that when calling these routines I am guessing a number of housekeeping side effect such as reading back registers, and applying soft reset is undertaken

So my question is, could I optimize these two calls into a single call, in order to not repeat some actions taken in both calls. In my application, speed is of the absolute essence, and clawing back a few ms will make all the difference.

I am happy to change/create (new wrapper) functions myself, but I can find no underlying documentation, which describes what actions are being taken and why, so I am concerned I could break something I do not understand whilst trying to optimize the call for freq & samplerate change

Any help or pointers, greatly appreciated

Thx Lee