[linux-dvb] tzap output concerns

Chun Chung LO cclo at astri.org
Mon Sep 24 06:41:20 CEST 2007


Hi,

But I noticed the UNC is not zero compared to the result in your first
mail. As far as I know, BER is high but UNC is zero, the signal should
be better than BER is low but UNC is NOT zero.

Am I right ?

Best regards,
Lo Chun Chung (Chung)
ECE-DHT at ASTRI HK.

-----Original Message-----
From: linux-dvb-bounces at linuxtv.org
[mailto:linux-dvb-bounces at linuxtv.org] On Behalf Of Dan Harper
Sent: Monday, 24 September, 2007 12:07 PM
To: linux-dvb
Subject: Re: [linux-dvb] tzap output concerns


Ah, it looks as though it's a bug in the Nova T 500 drivers.  To  
create the problem initially, I had turned down the amplifier on my  
antenna and then turned it up again.  I was then getting the poor  
results posted previously.  I have now booted the machine from a cold  
state and got the following results:

beastie:~# tzap -a 0 "ABC TV Melbourne"
using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
tuning to 226500000 Hz video pid 0x0200, audio pid 0x028a status 07 |
signal 8cd6 | snr 0000 | ber 001fffff | unc 00000022 | status 1f |
signal 8d1e | snr 0000 | ber 00000b90 | unc 00000038 |  
FE_HAS_LOCK
status 1f | signal 8d06 | snr 0000 | ber 00000670 | unc 0000002f |  
FE_HAS_LOCK
status 1f | signal 8d14 | snr 0000 | ber 00000100 | unc 0000002f |  
FE_HAS_LOCK
status 1f | signal 8d12 | snr 0000 | ber 00005af0 | unc 00000000 |  
FE_HAS_LOCK
status 1f | signal 8d1a | snr 0000 | ber 000005d0 | unc 00000108 |  
FE_HAS_LOCK
status 1f | signal 8d1d | snr 0000 | ber 00000310 | unc 00000000 |  
FE_HAS_LOCK
status 1f | signal 8d1e | snr 0000 | ber 000005f0 | unc 00000000 |  
FE_HAS_LOCK
status 1f | signal 8d77 | snr 0000 | ber 00000160 | unc 00000000 |  
FE_HAS_LOCK
status 1f | signal 8d0f | snr 0000 | ber 00000aa0 | unc 00000000 |  
FE_HAS_LOCK
status 1f | signal 8d4b | snr 0000 | ber 00000650 | unc 00000000 |  
FE_HAS_LOCK
status 1f | signal 8d18 | snr 0000 | ber 000004b0 | unc 00000000 |  
FE_HAS_LOCK
status 1f | signal 8d51 | snr 0000 | ber 00000630 | unc 00000028 |  
FE_HAS_LOCK

beastie:~# tzap -a 1 "ABC TV Melbourne"
using '/dev/dvb/adapter1/frontend0' and '/dev/dvb/adapter1/demux0'
tuning to 226500000 Hz video pid 0x0200, audio pid 0x028a status 0b |
signal 8fb5 | snr 0000 | ber 001fffff | unc 0000034c | status 1f |
signal 8f7f | snr 0000 | ber 000051a0 | unc 000008ad |  
FE_HAS_LOCK
status 1f | signal 8f7a | snr 0000 | ber 00000360 | unc 00000000 |  
FE_HAS_LOCK
status 1f | signal 8f99 | snr 0000 | ber 00000170 | unc 00000000 |  
FE_HAS_LOCK
status 1f | signal 8f9e | snr 0000 | ber 000008f0 | unc 00000002 |  
FE_HAS_LOCK
status 1f | signal 8f81 | snr 0000 | ber 000000e0 | unc 00000008 |  
FE_HAS_LOCK
status 1f | signal 8f92 | snr 0000 | ber 00002700 | unc 00000000 |  
FE_HAS_LOCK
status 1f | signal 8fac | snr 0000 | ber 0002cab0 | unc 00000000 |  
FE_HAS_LOCK
status 1f | signal 8fb7 | snr 0000 | ber 00000030 | unc 00000213 |  
FE_HAS_LOCK
status 1f | signal 8f97 | snr 0000 | ber 00000120 | unc 00000068 |  
FE_HAS_LOCK
status 1f | signal 8f65 | snr 0000 | ber 00000130 | unc 00000000 |  
FE_HAS_LOCK
status 1f | signal 8f5f | snr 0000 | ber 00000000 | unc 00000000 |  
FE_HAS_LOCK
status 1f | signal 8f94 | snr 0000 | ber 000000f0 | unc 00000000 |  
FE_HAS_LOCK
status 1f | signal 8fb8 | snr 0000 | ber 00000000 | unc 00000000 |  
FE_HAS_LOCK
status 1f | signal 8fa0 | snr 0000 | ber 00000000 | unc 00000000 |  
FE_HAS_LOCK

Not great, but better.

Hopefully this gives some more information for the developers to  
track down the bugs in the driver.  I'll try and figure out how to  
get this into the bug tracker.

Cheers,
Dan



On 24/09/2007, at 12:33 PM, Dan Harper wrote:

>
> On 24/09/2007, at 12:22 PM, Manu Abraham wrote:
>>
>> Please don't bother much about these statistics. These are a bit 
>> useless in most cases, ie it does vary driver to driver how it is
>> implemented.
>
> Thanks Manu, but I still have concerns because after Googling, I 
> notice that my results are not in line with other Nova T 500 users. 
> Actually the SNR is the same, but the BER and UNC is a cause for 
> concern.
>
> Dan
>
> _______________________________________________
> linux-dvb mailing list
> linux-dvb at linuxtv.org 
> http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb


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