How should sps differ in the usrp source usrp and usrp sink?

[pilot327]

Hi all
At the beginning I had Sample rate = “760ksps = samp_rate*6” in UHD: USRP Sink & Source. PIC 1 (01_flowgraph)

But the file was not received and gnuradio gave me WHD: Warning.. PIC 2 (whd_warning)


1.Why are sps for source and sps for sink not the same?

2.When I wrote suggested sps to source and sink, I still could not receive the video file. Why?

3.1 But when I wrote sps = 704000 = samp_rate*5.5 to source and(!) sink, the video file was received! Why? PIC 3 (whd_warning_2)

3.2 But I still had WHD: Warning. Why?

4. How can I get the right sps I must use (exactly 711111 not 704000!)?


I use gnuradio 3.7.10 and usrp1
Please answer the questions or say where i can find answers.
Thank you for your participation

 

[pilot327]

USRP TX/RX. Lost bytes and "U" in flowgraph execution

Hello everybody

I have the flowgraph below PIC 1 (01_01_flowgraph)
USRP transmits file (txt, picture and video) and receives this file at the same time.
Transmitted video is received without some bytes and i see letters "U". PIC 1 and PIC 2. at gnuradio terminal

1. What do this letters "U" mean?
1* I think there are anothers error letters. Where can i know about it?
2. I don't know on what it (letters) depends, but when i have 3 or more "U", video*doesn't play (but despite the lack of few bytes and 3 "U", received picture is displayed normal). Why?
3. Why I lost my bytes? PIC 2 (lost_bytes)

i use gnuradio 3.7.10 and usrp1.

Please answer the questions or say where i can find answers.
if you want to answer please do it considering i new in gnuradio and usrp.

 

[pilot327]

USRP Transmit speed and receive quality depend of file size and Payload Length at Pac

Hi,

i use this flowgraph PIC 1 (01_flowgraph)

USRP transmits file (txt, picture and video) and receives this file at the same time ( it is working flowgraph and you can use it free).

1. If i want to increase transmit speed i will increase PAYLOAD LENGTH in packet encoder. Is it the right way?

2.When I changed Payload Length in Packet Encoder
from 1 to 128 -- transmit speed increased from 4kb/s to 10kb/s
from 128 to 256 --* transmit speed increased from 10kb/s to 10.2kb/s

All of this changes work correctly only with files as of 61,2kb. When I try to transmit 5mb file, only 523kb are received. Why does it happen?

3. I thought that if I decreased samples/ symbol from 32 to 4 the transmit speed would increase. But it wasnt. Why?

4. When I wrote
in Packet Decoder:
** sps :32
** bps :8
** payload l: 1
and decreased sample_rate from 250k to 32k,only 3Mb out of 6Mb were received. Why does it happen? I thought only the transmit speed would decreased.

5. And why is receive width on PIC 2 (receive_width) not the same as transmit width PIC 3 (transmit_width)?
(QT sink was under the top_block when executing was running)
You can see that bandwidths of both QT sink are the same.

I use gnuradio 3.7.10 and usrp1.
I want to understand gnuradio logic and radiowave transmitting, but I am new in it.

Thank you for your answers.