Re: [Discuss-gnuradio] The RF LO does not support the requested frequency

[Daniele Nicolodi]

On 30/07/15 05:06, Nur Jalaudin wrote:
> hi. i am using ubuntu 14.04 and i am trying run wifi_rx.grc.when i try
> run this wifi_rx.grc it comes out with this:

[snip]

> UHD Warning:
>     The hardware does not support the requested RX sample rate:
>     Target sample rate: 5000.000000 MSps
>     Actual sample rate: 50.000000 MSps

[snip]

> UHD Warning:
>     The total sum of rates (50.000000 MSps on 1 channels) exceeds the
> maximum capacity of the connection.
>     This can cause overflows (O).
> O
>>>> Done
> 
> what should i do. i hope you can help me.

Hello,

what about reading and trying to understand the warning to obtain?

The first warning says that you requested a sampling rate of 5000 MSps,
or 5 GHz (!?!), which is obviously far higher that what the ADC can do,
I believe that there is no ADC that can sample at 5 GSps (if there is
one I would be very interested in getting one). The driver therefore
clamps your sample rate request to 50 MSps (which is the maximum
supported by your hardware).

The second warning is about the data transmission from the USRP (you do
not say, but from this message I believe it is an U2x0, with an USB
connection) to the host computer. The driver warns you that the
requested sampling rate (the 50 MSps from above), while supported by the
acquisition hardware, generates a volume of data that cannot be
transferred through the connection and that this will cause overflows.
Indeed this is what you obtain, as indicated by the 'O' that follows on
the output.

Are you sure you want a sampling rate of 5 GSps?

Cheers,
Daniele