I'm not so sure about there being a "restriction" on the 1500 due to USB
speed. Other SDRs successfully use USB at 192k, or possibly higher
sample rates. It might have been more costly (including licensing fees)
to put the Firewire chips in the 1500, but it was not due purely to USB
speed or buffering.
Having said that, I am convinced that a 100Mb or faster Ethernet
connection is the best longer-life (?) solution. You can argue about
UDP vs TCP (uP buffer sizing vs processing delay & complexity), but
those Ethernet ports are not going away anytime soon. Yes, most
computers have only one Ethernet connection, but with wireless becoming
ubiquitous, the wired net port is often available. If not, small
switches are cheap, and some run off DC power.
I was at Best Buy yesterday, and saw at least three laptops with
Firewire for under $1,000, one Toshiba and two Sonys. One Sony was
under $700. I love Firewire, coming from the TV broadcasting industry,
but I also see the writing on the wall. I always thought Firewire was
"better" than USB, but it turns out that USB is often "good enough". At
least if the drivers are available!
Terry, WB4JFI
On 2/12/2011 12:28 PM, Dan Scott wrote:
Interestingly our IT folks are running on new laptops (which I am not
yet on the list for). These new laptop are coming with Firewire.
Also there is a fundamental difference between Firewire and USB.
Firewire is a Direct Memory Access (DMA) protocol that uses the
bus-master to allocate and write directly into the memory
requested/allocated by the application while USB is a buffered
protocol requiring the data to be move from the buffer to the
application memory.
I assume one of the primary technical reason the1500 is restricted to
a sample rate of 48000 is that the additional latency of moving more
data from the USB buffer to the application memory (PowerSDR) would be
an issue. I was surprised when I saw the 1500 announced with the USB
interface because of this USB "tax".
Dan
On 2/12/2011 8:34 AM, Williams, Barry wrote:
Best Buy also carries the upper end of some brand name manufacturers
(HP, Sony). Several months ago I bought a Sony Vaio laptop with
HDMI, Express Card, Firewire, and USB with Nvidia display along with
the Intel core I7 processor and 3 GB RAM.
73,
Barry
KD5VC
------Original Message------
From: Tim Ellison
To: Alan NV8A
To: [email protected]
To: FlexRadio Reflector
Subject: Re: [Flexradio] USB3 - Firewire
Sent: Feb 12, 2011 8:31 AM
"What you get at Best Buy and other similar retailers is a machine
from which every last penny of manufacturing cost has been shaved.
And Best Buy still sells Firewire cards -- on line if not in every
store."
Well stated, Alan!
That is why I am a DYI PC builder or I get one from Neal (K3NC); I
want the pennies put back in. Yes, I have one of Neal's machines in
the shack. A techo piece of art (PC cubism at its finest) as well as
being a screaming fast machine.
Speaking of screaming fast machines, I saw with my own eyes Neal's
"ZERO DPC machine" at the Richmond FrostFest last weekend. I am a
believer.
-Tim
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Alan NV8A
Sent: Saturday, February 12, 2011 9:13 AM
To: [email protected]; FlexRadio Reflector
Subject: Re: [Flexradio] USB3 - Firewire
On 02/11/11 10:48 pm, [email protected] wrote:
I was perusing Best Buy today looking for a replacement household
computer and discovered virtually no systems with FireWire. The
salesman's pitch was that USB3 will be the functional replacement.
I believe he is right. I am not sure what USB3 speed is, but I'll
bet it handily outpaces Firewire. I know - latency is a different
matter.
Will Flex be offering 5000/3000 equivalents with USB3 connectivity?
My 1500 is a beautiful little USB2 package, so it looks like the
heavy lifting software wise has already been (is already being)
done. We surely
------Original Message Truncated------
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