[arm-allstar] usbradio

[David McGough]

Hi Bill,

The usbradio channel driver contains DSP software to detect carrier
squelch and perform PL tone decode / encode. Even with the, it's still
recommended to use the radio's native squelch and PL-tone capability,
since this usually provides superior results.

The chief drawback of using the DSP capabilities of the usbradio driver is
that all the DSP is performed in a single thread and must be performed in
real-time. While the RPi3 boards do in general have enough horsepower to
compute this workload, if anything interrupts this processing, the latency 
generated can/will generate audio pops and clicks.

Other issues with usbradio are that overall is has somewhat inferior audio 
fidelity and dynamic range, when compared to simpleusb. I haven't gone 
digging in the guts of this code to figure out why.

The simpleusb driver is clearly preferred, at this point. And, a new
channel driver, chan_iopipe, continues to make progress, slowly. Iopipe
includes a fully threaded floating-point DSP implementation. It's
optimized for the RPi3 and similar ARM hardware, utilizing multi-core
parallel computing.


73, David KB4FXC



On Sun, 11 Feb 2018, "Mr. Possum (Bill) via arm-allstar" wrote:

> Forgive me for scratching my head here...  But you say the node is in rx only mode that has no cos on the receiver...
> This may sound like a dumb question - but since there is no COS line on the node from the receiver, how does Asterisk know when the radios squelch opens so it will recognize it as being keyed up on receive?
> (Still scratching my head here...)
> Bill - N5MBM
> 
>       From: Tom Eaton via arm-allstar <arm-allstar at hamvoip.org>
>  To: ARM Allstar <arm-allstar at hamvoip.org> 
> Cc: Tom Eaton <kc4cbq at gmail.com>
>  Sent: Sunday, February 11, 2018 8:55 AM
>  Subject: [arm-allstar] usbradio
>    
> I am running 1.5rc4-14 and want to use usbradio and not simpleusb, I have set it up but cannot get it to work. these is the files. Works fine in simpleusb but when I change to usbradio radio-tune-menu will come up but it shows no audio on rx and will not tx, I am trying to test on a working node for a new rx only node that has no cos on receiver. Any help would be great.
> ThanksTom KC4CBQ
> 
> [usb1999]
> hdwtype=1 rxboost=1txboost=1rxctcssrelax=1txctcssdefault=100.0rxctcssfreqs=186.2txctcssfreqs=186.2;rxctcssoverride=0carrierfrom=dspctcssfrom=dsprxdemod=flattxprelim=yestxlimonly=notxtoctype=notonetxmixa=compositetxmixb=0invertptt=0duplex=1rxondelay=0rxnoisefiltype=0eeprom=0
> #includeifexists custom/usbradio.conf
> 
> 
> 
> [1999] ; Change this to your assigned node number 
> ; Channel Driver settings ; Define a channel driver to use and which ; interface within that channel driver ; To define a radioless node use the ; psuedo channel driver - rxchannel=dahdi/pseudorxchannel=Radio/usb1999 ; Example usbradio channel driver;rxchannel=SimpleUSB/usb ; Example simpleusb channel driver ;rxchannel=dahdi/pseudo                           
> 
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