Re: [Discuss-gnuradio] Evaluating PlutoSDR with DVB-T example dvbt_rx_8k

[Ron Economos]

I believe the sample rate of 8 MHz DVB-T is beyond the capability of the Pluto. The required sample rate is 9.14 Msps, which exceeds the throughput of USB 2.0.

Ron

On 11/13/18 10:33, Rudolf Wigblurr wrote:

Hi!

I'm validating if a new ADALM-PLOTO is fully working or not.
Attached is a modified version of the dvbt_rx_8k example (test_dvbt_rx_8k_copy.grc)

 

1. Source from adv64.cfile

 

A correct result I think.
Both Constellation are steady even with noise added.
See "test_dvbt_rx_8k_copy.adv64.png"

 

2. Source from PlutoSDR

 

Incorrect.
First Constellation shows signs of pilot but it is not stable at all.
Second Constellation show just a dot.
See "test_dvbt_rx_8k_copy.pluto.png" and "animated.gif"

 

Input is the local terrestrial TV from my antenna on the roof.

According to the Terrestrial broadcast company there are 4-modes for DVB-T

 

Bandwidth: 8MHz
FFT size: 8k
Modulation: 64QAM
Guard Interval:  1/4, 1/8, 1/32, 1/4
Code Rate:  3/4, 2/3, 2/3, 2/3
Hierarchical: non

 

Played around with a lot figures without getting anything better than attached gif
There are no signs of overruns.

CPU load is 100% on one core rest 5-10% on a i7-4770K @ 3.5

 

OS Fedora 29
Kernel 4.18.17-300.fc29.x86_64
GNU Radio Companion 3.7.13.4
PLUTO build from latest git

 

Is Pluto skipping or ....?

 

/Rudolf

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