[App_rpt-users] Audio Clipping with IAXRPT / Web Transceiver Client

[Keith Goobie]

Hi Robert

Memory on the system is 1GB ram

When I run free I get -

[root at VE3LSR asterisk]#  free
             total       used       free     shared    buffers     cached
Mem:       1034368     628924     405444          0     185776     289968
-/+ buffers/cache:     153180     881188
Swap:      1020116          0    1020116
[root at VE3LSR asterisk]#

The attached drive is a SSD

Clipping can occur randomly ­ it is not tied to one station.  Volume levels
on these stations can vary.

We have good bandwidth into out of the site.  Co-located with an ISP.

We are using the DMK fobs.

Keith



On 3/3/13 12:48 PM, "Robert a. Poff" <wb3awj at comcast.net> wrote:

> Does the clipping occur usually on the same stations?
> Or sort of randomly?
> 
> In addition to CPU load, how much free memory do you have?
> I was told that you should have enough memory to not see ANY swapping.
> And found that to be a good rule of thumb.
> The time involved with disk access comes into play.
> 
> 
> Keith Goobie <keith at goobie.org> wrote:
>> Good day All.
>> 
>> We have had our node up at VE3LSR / VE3UOR for a few months and we all have
>> learned a lot about configuration and operation.  It is ACID install and
>> version id is 300.3.
>> 
>> On our asterisk system, we support three nodes:
>> 
>> 27211 ­ VE3UOR UHF repeater
>> 29133 ­ VE3LSR coupled through a RLC-DSP404 controller (often connected to
>> VE3UPS and VE3UHN), and
>> 29154 ­ VA3LSR remote link for VE3LSR into VE3MUS ­ not too active ­ ad-hoc
>> RF link.
>> 
>> I have also been testing out iaxrpt and the WebTransceiver clients.
>> 
>> I am on these systems and the results have been promising.  I do notice some
>> clipping on the audio on some stations.  Initially I thought it was amplitude
>> related ­ over-driving the URI-FOB, but I am now beginning to suspect that it
>> may be network related and in my research I hear the term jitter being used ­
>> which if activated, adjust operation on the receiving end only.
>> 
>> It may be that the system is not powered enough to drive the three uri-fobs.
>> CPU show about 25% busy.
>> [root at VE3LSR etc]# cat /proc/cpuinfo
>> processor    : 0
>> vendor_id    : GenuineIntel
>> cpu family    : 15
>> model        : 4
>> model name    : Intel(R) Pentium(R) 4 CPU 3.00GHz
>> stepping    : 3
>> cpu MHz        : 2992.898
>> cache size    : 2048 KB
>> physical id    : 0
>> siblings    : 2
>> core id        : 0
>> cpu cores    : 1
>> apicid        : 0
>> fdiv_bug    : no
>> hlt_bug        : no
>> f00f_bug    : no
>> coma_bug    : no
>> fpu        : yes
>> fpu_exception    : yes
>> cpuid level    : 5
>> wp        : yes
>> flags        : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat
>> pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe lm constant_tsc pni
>> monitor ds_cpl est cid cx16 xtpr
>> bogomips    : 5985.79
>> 
>> We do think that the system is sufficiently powered.
>> 
>> We are looking for comments & guidance.  Are we expecting too much from the
>> system having three fobs connected?  We do have good bandwidth into and out
>> of the site.  
>> 
>> I am listening to other systems ­ most not to busy, so I am not yet able to
>> get a good reference point.
>> 
>> I have not dabbled with the codecs much, but have been focused on using ulaw.
>> I am also testing with GSM ­ lower bandwidth.
>> 
>> So as I said before, thoughts or suggestions are welcome.
>> 
>> Keith / VA3YC

-- 
keith at goobie.org
Keith Goobie
Richmond Hill, ON, CANADA

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