Hi Simon,

Will ASIO be supported? The latency can be made very low with ASIO drivers! See http://www.lz1aq.signacor.com/docs/std/Measurements_of_Signal_Time_Delays_in_Several_SDR.htm

Steve-M0ZEH

Hi Simon

It's nice to see that new items are on the horizon from RFspace.
I do hope that features that are being added will still take into
account the vast number of IQ's out here. Would be nice to have an
SDR-IP but I can live with the spectrum confines of the IQ.
Growth in the SDR world seems to be like the growth of computers
where what was the latest and greates is old news in 6 months. Just my 2 cents worth.

Jim

Hi Simon

Sounds like many things coming up. Just don't want to loose
basic functional support for the IQ's.
In any case I always have HRD and the R-75 to fall back on.

Jim

Hi Steve,

Will ASIO be supported? The latency can be made very
low with ASIO drivers! See http://www.lz1aq.signacor.com/docs/std/
Measurements_of_Signal_Time_Delays_in_Several_SDR.htm

I am right now in the process of checking the delay from
antenna to loudspeaker in Linrad with various combinations
of hardwares, drivers and operating systems.

With Perseus and Delta 44 ASIO through Portaudio the time
is just below 10 ms on these systems:
Debian Linux
XP 32
XP 64
Vista 32
Win7 32

The WDM-KS and WASAPI drivers are typically 1 ms slower on systems
where they exist.

The motherboard sound system Sigmatel (Intel) does not have ASIO
drivers. Under Vista 32 there is a WASAPI driver which gives 11 ms
delay.

With SDR-IP as the signal source I see the following times:

Debian Linux: 12 ms
XP 32: 23 ms
XP 64: 25 ms
Vista 32: 9 ms
Vista 64: 25 ms
Win7 32: 25 ms

The long times are due to buffering somewhere inside Windows.
Presumably one can set buffering parameters somewhere but I
have not (yet?) any idea about how to do that. Only Vista 32
has suitable default buffer sizes for the network.

When I use the SDR-14 as input, the delay typically increases by
13 ms at a sampling rate of 190 kHz. (The fixed size buffers of 8192
bytes in SDR-14 correspond to 10.8 ms)

The MME drivers under Windows give delays in the range 50 to 100 ms.

The above times are with SSB bandwidth on a fast computer with
the smallest buffers that Linrad can set. ("DMA rate" about 750 Hz)

Portaudio is only useful for ASIO, WDM-KS and WASAPI. It does not
work at all (with small buffers) for MME and direct sound and it
also does not work with ALSA under Linux.

Vista 64 and Win7 64 remain. Right now I am trying to understand
why I can not run Linrad with Perseus under Vista 64.

Anyway, this statement is certainly true: "The latency can be made very
low with ASIO drivers!" and also WASAPI and WDM-KS may be good although
not necessarily so. Under Win7 the Sigmatel WASAPI driver goes through
the mixer program which delays by 6 ms extra.

It is obvious that we can make SDR transceivers with adequate
response times for QSK and contesting. But the old MME drivers
(Windows Multimedia Extension) will not be acceptable.

73

Leif / SM5BSZ

--- In sdr-radio-com@..., Leif Asbrink <leif@...> wrote:

Hi Steve,

Will ASIO be supported? The latency can be made very
low with ASIO drivers! See http://www.lz1aq.signacor.com/docs/std/
Measurements_of_Signal_Time_Delays_in_Several_SDR.htm

I am right now in the process of checking the delay from
antenna to loudspeaker in Linrad with various combinations
of hardwares, drivers and operating systems.

With Perseus and Delta 44 ASIO through Portaudio the time
is just below 10 ms on these systems:
Debian Linux
XP 32
XP 64
Vista 32
Win7 32

The WDM-KS and WASAPI drivers are typically 1 ms slower on systems
where they exist.

The motherboard sound system Sigmatel (Intel) does not have ASIO
drivers. Under Vista 32 there is a WASAPI driver which gives 11 ms
delay.

With SDR-IP as the signal source I see the following times:

Debian Linux: 12 ms
XP 32: 23 ms
XP 64: 25 ms
Vista 32: 9 ms
Vista 64: 25 ms
Win7 32: 25 ms

The long times are due to buffering somewhere inside Windows.
Presumably one can set buffering parameters somewhere but I
have not (yet?) any idea about how to do that. Only Vista 32
has suitable default buffer sizes for the network.

When I use the SDR-14 as input, the delay typically increases by
13 ms at a sampling rate of 190 kHz. (The fixed size buffers of 8192
bytes in SDR-14 correspond to 10.8 ms)

The MME drivers under Windows give delays in the range 50 to 100 ms.

The above times are with SSB bandwidth on a fast computer with
the smallest buffers that Linrad can set. ("DMA rate" about 750 Hz)

Portaudio is only useful for ASIO, WDM-KS and WASAPI. It does not
work at all (with small buffers) for MME and direct sound and it
also does not work with ALSA under Linux.

Vista 64 and Win7 64 remain. Right now I am trying to understand
why I can not run Linrad with Perseus under Vista 64.

Anyway, this statement is certainly true: "The latency can be made very
low with ASIO drivers!" and also WASAPI and WDM-KS may be good although
not necessarily so. Under Win7 the Sigmatel WASAPI driver goes through
the mixer program which delays by 6 ms extra.

It is obvious that we can make SDR transceivers with adequate
response times for QSK and contesting. But the old MME drivers
(Windows Multimedia Extension) will not be acceptable.

73

Leif / SM5BSZ

Thanks for your reply and all others. The lower the delay the better as I work IC-746 for transmit and Softrock for receive. Any delays can get a bit confusing!
This part of the hobby still gets me excited and I can't wait for Simon's Rig control to sync the Icom with the SDR.
73 Steve-M0ZEH