Retrieving device type

Kevin Reid kpreid at switchb.org
Tue Mar 4 01:08:27 UTC 2014


On Mar 3, 2014, at 14:02, Alexandru Csete <oz9aec at gmail.com> wrote:
> On Mon, Mar 3, 2014 at 10:35 PM, Nick Foster <bistromath at gmail.com> wrote:
>> Hi,
>> 
>> gr-osmosdr is great at abstracting the device type, but now I find myself
>> wishing to de-abstract. For instance: HackRF has large DC offset, so I'd
>> like the option to switch in a DC blocking filter when using that source.
>> RTL dongles can't support more than 2.4Msps reliably, so I'd like to be able
>> to cope accordingly at initialization time.
>> 
>> Is there a good way to retrieve, say, a string descriptor telling me which
>> particular source I'm using?
> 
> None that I know of, but aren't you the one who decides what device is
> in use by passing e.g. "hackrf=0" as argument to the constructor?

My own project is unrelated to the original poster's, but I'd also like to see this feature. I'm *not* deciding what device to use -- the user is giving a device string in my application's configuration. I could parse the config string, but then I'm reimplementing parts of gr-osmosdr (note that it can have "a=b" parameters which are not themselves device specifications, and might even come first, or at least that used to be a possibility). Being able to ask gr-osmosdr is good factoring.

Even then, the config string is less specific than might be useful: for example, RTL devices all match "rtl=...", but have different RF characteristics (for example, those with the E4000 chip have a DC offset but R820Ts do not, and they also have different gain and filtering behavior).

This information is available to the underlying driver, obviously as it prints messages like "Using device #0 Realtek RTL2838UHIDIR SN: 1E" and "Found Elonics E4000 tuner"; I'd just like to have that amount of detail exposed. (The first part but not the second is available if you are using osmosdr.device_find().)

-- 
Kevin Reid                                  <http://switchb.org/kpreid/>





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