[Hackrf-dev] GNU Radio and HackRF and Latency

[Mitja kocjančič]

Hi I am transmitting FM Modulated signal on 76 Mhz  and recieving it on my
Sangean ATS 909X

The signal is normal FM Radio signal with RDS and Stereo but for some
reason there is 1 second delay (when I change song for instance it takes 1
seconds for my Radio to notice that)

Thats strange to me because I always thought that FM Modulation happens in
real time and when you say something into microfone radio will pick
it immediately.

I know that 1 second delay happens with DAB (because you must encode audio
and then decode it) but not on FM

So could anybody be so kinf and tell me the reason why this delay happens
and how to overcome this.

Thanks for Anwsering and Best Regards
___
HackRF-dev mailing list
HackRF-dev@greatscottgadgets.com
https://pairlist9.pair.net/mailman/listinfo/hackrf-dev

Re: [Hackrf-dev] GNU Radio and HackRF and Latency

[Tamer Çelik]

Hello Mitja,

Any chance that you are using Virtualbox?
It's really buggy with USB drivers and may cause a delay.
On Dec 4, 2015 3:47 PM, "Mitja kocjančič"  wrote:

> Hi I am transmitting FM Modulated signal on 76 Mhz  and recieving it on my
> Sangean ATS 909X
>
> The signal is normal FM Radio signal with RDS and Stereo but for some
> reason there is 1 second delay (when I change song for instance it takes 1
> seconds for my Radio to notice that)
>
> Thats strange to me because I always thought that FM Modulation happens in
> real time and when you say something into microfone radio will pick
> it immediately.
>
> I know that 1 second delay happens with DAB (because you must encode audio
> and then decode it) but not on FM
>
> So could anybody be so kinf and tell me the reason why this delay happens
> and how to overcome this.
>
> Thanks for Anwsering and Best Regards
>
> ___
> HackRF-dev mailing list
> HackRF-dev@greatscottgadgets.com
> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
>
>
___
HackRF-dev mailing list
HackRF-dev@greatscottgadgets.com
https://pairlist9.pair.net/mailman/listinfo/hackrf-dev

Re: [Hackrf-dev] GNU Radio and HackRF and Latency

[Mitja kocjančič]

Thanks and How I can aplpy this patches?

PS: what do you think with dropped samples?

PPS: @ I can't use HackRF in virtualized enviroment

2015-12-04 17:48 GMT+01:00 Mike Walters :

> The issue is caused by large sample buffers, mainly the USB buffer size.
>
> I've worked around it before by just patching gr-osmosdr and libhackrf to
> use smaller buffers. This isn't a great fix because it will increase chance
> of dropped samples at high rates. Here are the patches:
>
> https://github.com/miek/gr-hubsan/blob/master/hackrf-16k-buffer.diff
> https://github.com/miek/gr-hubsan/blob/master/gr-osmosdr-16k-buffer.diff
>
> You may also need to play around with GNURadio max. buffers as discussed
> here:
>
> https://gnuradio.org/doc/doxygen/page_operating_fg.html#latency
>
>
> On 4 December 2015 at 13:47, Mitja kocjančič  wrote:
>
>> Hi I am transmitting FM Modulated signal on 76 Mhz  and recieving it on
>> my Sangean ATS 909X
>>
>> The signal is normal FM Radio signal with RDS and Stereo but for some
>> reason there is 1 second delay (when I change song for instance it takes 1
>> seconds for my Radio to notice that)
>>
>> Thats strange to me because I always thought that FM Modulation happens
>> in real time and when you say something into microfone radio will pick
>> it immediately.
>>
>> I know that 1 second delay happens with DAB (because you must encode
>> audio and then decode it) but not on FM
>>
>> So could anybody be so kinf and tell me the reason why this delay happens
>> and how to overcome this.
>>
>> Thanks for Anwsering and Best Regards
>>
>> ___
>> HackRF-dev mailing list
>> HackRF-dev@greatscottgadgets.com
>> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
>>
>>
>
___
HackRF-dev mailing list
HackRF-dev@greatscottgadgets.com
https://pairlist9.pair.net/mailman/listinfo/hackrf-dev