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Author Topic: SDR Knobs and Buttons in the future  (Read 88360 times)
AA4PB
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Posts: 12667




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« Reply #15 on: August 16, 2013, 02:37:23 PM »

The problem with a radio is that it operates at radio frequencies (much higher than A/D, D/A, and DSP can function with current technology) so you can't just connect the antenna to a sound card. The DSP work (filtering, modulation, and demodulation) must be done at frequencies far below the radio's operating frequency. This still requires hardware for the front end of the receiver and final stages of the transmitter. I believe this hardware represents the major cost of an SDR transceiver so moving the modulation, demodulation, and user interface to a PC doesn't reduce the cost all that much even when you don't count the cost of the PC.

That's quite different (I think) than a sound studio application where the highest frequency involved is audio that is well within the capabilities of standard off-the-shelf A/D, D/A, and DSP chips. In spite of this, I still see lots of live mixing applications where a dedicated mixing console is used rather than a PC. The processing is mostly DSP but it is done with firmware in the console rather than software on a general purpose PC. The most used functions are still controlled by knobs and sliders as user input to the firmware. This is where I think amateur radio transceivers are headed in the long run (of course I could be wrong Grin).

The other consideration (in my opinion) is that the majority of hams still want transceivers that are self contained, transportable, and relatively easy to operate. Having a box connected to a PC along with remote tuning and control devices plus dealing with loading and configuring software, drivers, etc. doesn't really lend itself well to that requirement.
 
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SWL2002
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« Reply #16 on: August 16, 2013, 04:48:04 PM »

The problem with a radio is that it operates at radio frequencies (much higher than A/D, D/A, and DSP can function with current technology) so you can't just connect the antenna to a sound card. The DSP work (filtering, modulation, and demodulation) must be done at frequencies far below the radio's operating frequency. This still requires hardware for the front end of the receiver and final stages of the transmitter. I believe this hardware represents the major cost of an SDR transceiver so moving the modulation, demodulation, and user interface to a PC doesn't reduce the cost all that much even when you don't count the cost of the PC.

That's quite different (I think) than a sound studio application where the highest frequency involved is audio that is well within the capabilities of standard off-the-shelf A/D, D/A, and DSP chips. In spite of this, I still see lots of live mixing applications where a dedicated mixing console is used rather than a PC. The processing is mostly DSP but it is done with firmware in the console rather than software on a general purpose PC. The most used functions are still controlled by knobs and sliders as user input to the firmware. This is where I think amateur radio transceivers are headed in the long run (of course I could be wrong Grin).

The other consideration (in my opinion) is that the majority of hams still want transceivers that are self contained, transportable, and relatively easy to operate. Having a box connected to a PC along with remote tuning and control devices plus dealing with loading and configuring software, drivers, etc. doesn't really lend itself well to that requirement.
 


Its pretty simple to understand the cost of a DDC/DUC SDR that performs up there with the best superhet analog designs.  High speed 16 bit ADCs are expensive, something in the neighborhood of $100 ea in smaller quantities.  Compare that to analog solid state devices used in the front end of an analog receiver where those devices cost 25-50 cents each.   You also need DDC/DUC hardware, which is usually implemented in a FPGA.  There are dedicated DDC/DUC integrated circuits but they are developed for the cell phone base station market and do not offer enough dynamic range and alias free bandwidth.  The FPGAs, in which the designer implements a high performing DDC/DUC, can cost from $25 each up to a couple thousand dollars each depending on capabilities.  Still much more expensive than the discrete analog devices used in a superhet or analog direct conversion design.  You also have to throw in software development costs if the SDR manufacturer produces their own software for their hardware (A must, IMO, if you want good integration of a manufacturers hardware with the software).

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KF6QEX
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« Reply #17 on: August 17, 2013, 03:38:36 AM »

For Ford, the future is now:
http://www.edn.com/electronics-blogs/automotive-innovation/4418518/Touch-control-not-always-the-best-solution



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K9IUQ
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Posts: 1626




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« Reply #18 on: August 17, 2013, 04:05:30 AM »


Ah yes. I have a KIA Soul with a fancy tablet interface and voice controlled Radio.
I hate it. The touch screen is very distracting to use while driving. And the voice control does not work half the time because I do not have a South Korean accent. Give me knobs and old fashioned push button radio any day.

Stan K9IUQ
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W6RMK
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Posts: 649




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« Reply #19 on: August 17, 2013, 07:37:41 AM »

I'm kind of surprised that SDRs are so expensive.  Eliminating the front end of something like a Flex should make it much, much cheaper to design and manufacture than a traditional radio.

It's more that traditional radios are abnormally cheap. Something like an IC-7000 for a bit more than $1000 is an awful lot of radio functionality in a fairly small box.  While the boat anchor folks are justly proud of their units, in real dollars, you spent a lot of bucks for not much in the way of performance.

After that, it's all about mass production. You need fairly high volumes to get the price down. But even with that, it's hard to get the parts count really down.  Sure, one can build a minimalist radio with very few parts (look at the $20 USB tuner based radios), but there will be some performance issues.  On receive, wide open front end means that strong adjacent signals will cause problems.  On transmit, you need output filters for harmonic suppression, and it's hard to get really good carrier/image suppression.  Getting 100W RF power from 2-30 MHz is also challenging at low cost, even with crummy performance.

It all adds up. And it all  takes different pieces of the puzzle, so there's not as much to be gained by higher levels of integration. It's not like you can integrate the HF power amp with the required output filter and put it all on one die in one package.

Even things like power supply bypass capacitors and biasing stuff adds up. The block diagram may only have half a dozen "building blocks", but each of those requires 10-15 passive components hanging around it to make it work.

That said, I think there is scope for some clever design that has not seen the production light of day. The merging of software control that can compensate for DAC and PA non-ideal behavior, and manage things like bias and power supply output on the fly might make transmitters simpler, more efficient, etc.  But that is hard to implement successfully.  Sure you can do cartesian/polar modulation, but it tightly couples the power supply design, the power amplifier, and the low level outputs, whcih makes the design of all of those more tricky.  You don't get to leverage the last 50 years of transistor amplifier design as much.

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K5TED
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Posts: 691




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« Reply #20 on: August 17, 2013, 07:24:57 PM »

It's always amazing to witness the utterly obtuse ignorance of reality with those who can't seem to understand that with a Flex or any other thick pipe SDR, the PC that controls the radio is part of the radio, not some incidental ancillary function of your main PC that you use for Facebook and playing Farmville on.

There is absolutely no precedence set by the manufacturers saying that you should not invest in a dedicated PC for controlling your SDR, nor is there any anecdotal evidence of merit that makes that assertion with any sort of validity.

You wouldn't expect to use your Yaesu FT-2000 front panel for logging on to Twitter, so why would you expect to use your Twitter capable PC to run an SDR?

SDR. You either get it or you don't. If you don't, it's not a bad thing, but don't blame it on the rest of us who do get it. We know you're special...
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KF6QEX
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Posts: 589




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« Reply #21 on: August 18, 2013, 05:04:08 AM »

Quote
The other consideration (in my opinion) is that the majority of hams still want transceivers that are self contained, transportable, and relatively easy to operate. Having a box connected to a PC along with remote tuning and control devices plus dealing with loading and configuring software, drivers, etc. doesn't really lend itself well to that requirement.

Nicely summarized

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K9IUQ
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Posts: 1626




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« Reply #22 on: August 18, 2013, 05:46:33 AM »

the PC that controls the radio is part of the radio,

Exactly correct. Window Computers were never designed or meant for real time applications like Hamradio. Which of course is one the reasons Flexradios and other SDR's will never be mainstream hamradios.

Stan K9IUQ
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HAMMYGUY
Member

Posts: 83




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« Reply #23 on: August 18, 2013, 10:31:14 AM »

K5TED my experience with most of my Flex rigs (I've had 2 1000's, 2 1500's and 2 3000's) has been nothing but frustrating.  These radios should have have the CW function blocked on PowerSDR.  Yes I was using a super duper fantastic computer with a zillion megabyte processor with the highly blessed and completely obsolete Firewire interface (unless you're into the music scene).  And yet now it's been proven by the HpSDR folks that PowerSDR IS capable of working with Ethernet. Which completely eliminates the CW lag using my Anan radio which runs on an old POS computer with no issues. 

THAT's why my Flex rigs are all out the door.  CW doesn't work on them unless you're used to,

Press Key "DIT".........................................................................................(wait for it)........................................................................................"Dit" (going out over the air).   
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KK6GNP
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Posts: 158




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« Reply #24 on: August 18, 2013, 11:36:58 AM »

the PC that controls the radio is part of the radio,

Exactly correct. Window Computers were never designed or meant for real time applications like Hamradio. Which of course is one the reasons Flexradios and other SDR's will never be mainstream hamradios.

Stan K9IUQ

PCs are very good at "real time" data stream processing, as long as you are matching your hardware specs with the needs of the software you are using.  My home desktop computer could process a full SDR stream, play a high end 3D video game, and capture live video from a video camera all at the same time, without even breathing hard.  Granted, I built my machine to be a monster, but the reality today is that our computer hardware largely exceeds the demands of today's software.  Especially with quad and hex core processors, cheap memory, and fast hard drives.

Another aspect of problems with SDR seems to be people trying to get them to run on old hardware.  I've only been around here for a short time, but from what I've seen of ham shack photos, and people talking about their computers, there is a lot of ancient computers still being used by hams.  For about $500-600 you could build a new computer with a mid-grade quad core CPU, 8gigs of ram, and a decent hard drive that would process SDR streams and more with no problems at all.

For kicks, here's a picture of my latest build.  I gave myself a $2000 budget to set up a nice gaming rig this year.  I spent $3K on my last one a few years ago, but hardware is cheaper and much more powerful now.  Uses a lot less power too.

http://i.imgur.com/Q5zgF.jpg
« Last Edit: August 18, 2013, 11:52:39 AM by JEEPESCAPE » Logged

73 ~ Cory (JeepEscape)
KK6GNP
KK6GNP
Member

Posts: 158




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« Reply #25 on: August 18, 2013, 11:43:57 AM »

I also wanted to add that as far as latency/lag goes for things like CW, using DSP instruments and effects plugins on computers demand low latency as well, in the range of 1-3ms.  If there is a delay, there could be problems with either the computer's ability to keep up, or latency issues/bugs in the software being used.  This is a very subjective situation.

Not all firewire controllers are equal, and if the SDR needs a sound card, there are varying degrees of performance in that area too.  Coming from video gaming on PC's, I would go out and get a good Soundblaster sound card, and purchase a low latency firewire controller like the ones used for music and video production.

I agree that Firewire is obsolete and should be abandoned.  Thunderbolt should be considered.
« Last Edit: August 18, 2013, 11:55:43 AM by JEEPESCAPE » Logged

73 ~ Cory (JeepEscape)
KK6GNP
WB2ZXJ
Member

Posts: 8




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« Reply #26 on: August 18, 2013, 12:00:40 PM »

...
For kicks, here's a picture of my latest build.  I gave myself a $2000 budget to set up a nice gaming rig this year.  I spent $3K on my last one a few years ago, but hardware is cheaper and much more powerful now.  Uses a lot less power too.

http://i.imgur.com/Q5zgF.jpg
[/quote]



OT, but:

Very nice!   And, water cooled.

Barry
WB2ZXJ
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K9IUQ
Member

Posts: 1626




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« Reply #27 on: August 18, 2013, 12:07:33 PM »


The problems with PCs in radio, and elsewhere, come from people not paying attention to minimum system requirements for their application.

Not so. Desktop Windows is not a RTOS real time operating system. Use Google, he is your friend and you can also find some RTOS that will do Real Time.

Myself and others had way over the minimum computer requirements for PSDR. And still CW had lag. Still had to worry and contain DPC's. DPC's =A Deferred Procedure Call (DPC) is a Microsoft Windows operating system mechanism which allows high-priority tasks (e.g. an interrupt handler). I assume you understand interrupts and something can not be real time if it interrupts processes...

I tried 3 different computers on PSDR. A full blown i7 with all goodies and fasttt, an i3 laptop loaded and and another computer which I had laying around and do not remember what it was but it was over bare minimum requirements. I also tried a dedicated PC for PSDR. I also tried WIn 7, Vista and Win XP, and Win ME none of which made any difference. As long as Windows uses interrupts SDR software will suffer. Latency, no matter how short affects SDR software. It also made sending CW next to impossible without using an external keyer or (ugh) a keyboard.

I also had to try a couple of different Firewire cards as PSDR only likes one particular chipset of Firewire. You do remember Firewire.  Cheesy

PSDR was also very particular on how you treated it. I lost count of how many times I had to reset the database and or reboot.  Wink

when you own a Flexradio you must have patience and learn how to jump thru hoops..

Stan K9IUQ



 
« Last Edit: August 18, 2013, 12:23:42 PM by K9IUQ » Logged
K9IUQ
Member

Posts: 1626




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« Reply #28 on: August 18, 2013, 12:16:17 PM »

These radios should have have the CW function blocked on PowerSDR.  Yes I was using a super duper fantastic computer with a zillion megabyte processor with the highly blessed and completely obsolete Firewire interface (unless you're into the music scene). 

CW doesn't work on them unless you're used to,

Press Key "DIT".........................................................................................(wait for it)........................................................................................"Dit" (going out over the air).   

Yep. Flexradios are for SSBers only as I have said many times on this forum. I got rid of my 5K for several reasons and CW performance was at the top of the list.

Stan K9IUQ

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KK6GNP
Member

Posts: 158




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« Reply #29 on: August 18, 2013, 12:17:06 PM »


The problems with PCs in radio, and elsewhere, come from people not paying attention to minimum system requirements for their application.

Not so. Desktop Windows is not a RTOS real time operating system. Use Google, he is your friend and you can also find some RTOS that will do Real Time.

Myself and others had way over the minimum computer requirements for PSDR. And still CW had lag. Still had to worry and contain DPC's. DPC's =A Deferred Procedure Call (DPC) is a Microsoft Windows operating system mechanism which allows high-priority tasks (e.g. an interrupt handler). I assume you understand interrupts and something can not be real time if it interrupts processes...

I tried 3 different computers on PSDR. A full blown i7 with all goodies and fasttt, an i3 laptop loaded and and another computer which I had laying around and do not remember what it was but it was over bare minimum requirements. I also tried a dedicated PC for PSDR. I also tried WIn 7, Vista and Win XP, and Win ME none of which made any difference. As long as Windows uses interrupts SDR software will suffer. Latency, no matter how short affects SDR software. It also makes sending CW next to impossible without using an external keyer.

I also had to try a couple of different Firewire cards as PSDR only likes one particular chipset of Firewire. You do remember Firewire.  Cheesy

Stan K9IUQ
 

Stan, you do realize that the entire music and movie industry uses Windows and Mac (mostly Mac) for production, yes?  ProTools is one of the most well known software suites for production, and it requires very low latency for timing with digital instruments, recording equipment, synthesizers, DSP plugins and effects, etc.  Unless you think CW requires less than a few milliseconds of latency, then I don't really know why you think you need a special operating system.

I want to be clear that I am not defending Flex here.  I've never touched one.  I'm speaking in terms of computers and somewhat similar low-latency uses for them all over the world.  I want people to understand that standard desktop computers are more than capable of doing very low latency operations with external hardware. If this wasn't true, then they wouldn't be used for music and movie production.

Flex's software/hardware may have issues with CW, I don't know, but that wouldn't be some inherent flaw with PCs that I'm aware of.  I'd be interested to see Flex SDR's latency numbers, if anyone has a link.  Surely they have been tested with CW.
« Last Edit: August 18, 2013, 12:32:48 PM by JEEPESCAPE » Logged

73 ~ Cory (JeepEscape)
KK6GNP
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