Yup. Superhet and then one of these puppies, under a buck:
-- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
of
books
Sonar? In Arizona? You guys don't even have an ocean :-)
-- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
What frequency ranges and how steep are the skirts though?
And what is the tuning mechanism?
Yep.
Did you have much luck with their insurance offerings?
---Joel
Yup. Not to mention that the dynamic range of most ADC's is a huge restriction. The more you can control the bandwidth before conversion the better off you'll be.
Or a ceramic one, depending on your app.
-- www.wescottdesign.com
Typical ranges are 4-6MHz, 6-9MHz, 11-15MHz, 17-22MHz and similar. The steepness isn't that great, something like 8MHz at -6dB and -60dB at
9MHz, for example. If the OP needs stellar channel rejection he has IMHO only two options, superhet or DSP.Varicaps, usually. However, purchasing duals in order to be able to servo has become a bear. And one has to remain friends with the purchasing department since those are the guys who get all the Christmas bonbons :-)
Nope, they couldn't do it :-(
-- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
[...]
It almost has to be. I don't think you can buy 600kHz wide crystal filters.
-- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
of
books
fixed
Oh, yeah! We have farm-raised shrimp ;-) ...Jim Thompson
-- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | If you wanted a President with balls why didn\'t you elect Hillary?
Ouch! You mean six active elements? That makes the fast opamp solution a lot harder.
George H.
"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...
Farm raised shrimp, aren't they rubbery and bland. Buy only wild caught Florida shrimp.
Mike
Farm grown shrimp are excellent.... and _disease_free_. (Artificial salt water lakes... a giant version of my aquarium ;-)
They're working on a similar concept for oysters.
...Jim Thompson
-- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | If you wanted a President with balls why didn\'t you elect Hillary?
of
books
fixed
But he had a customer in Santa Barbara.
A average analogue hf comms radio probably has a dynamic range of 0.5uV to 1v or better at the antenna terminals and it would take a pretty special fast adc to get near that.
So what is the current state of the art in sdr, using commodity hardware ?...
Regards,
Chris
For HF work, these guys are popular:
They are many others out there... another popular one is the TAPR "HPSDR" (high performance SDR) kits.
---Joel
of
books
fixed
Ok, that counts. I've tried to get away from ultrasound because it's mostly been medical and there is no more liability coverage available in the US. But it always snags me back, like a couple weeks ago and now it seems I'll be right back in there.
-- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
Yes, 24 bits would be enough and quite impressive at a 192Khz sample rate. The technology is moving fast these days :-).
Haven't done much radio for years. Still have an old 60's Plessey PR155 radio in the lab, which has an early (1965) quad discreet schottky diode front end up converted to a 37.3 Mhz ist if, with a roofing filter at
15Khz bw. I remember the hp schottky diodes were called 'hot carrier'. Fairly radical at the time and far better than the Racal equivalent radio's, but pretty standard technique now.Current technology is starting to look really interesting, though I think Collins built a digital back end radio over a decade ago...
Regards,
Chris
So what kind of things do you work on these days?
John Larkin likes to draw them in a way that suggests their "hot carrier" nature...
Same with the military -- the big change has been that this stuff has become affordable to the average person.
I'm surprised how quickly the Flex Radio guys have grown... I remember it being only something like 4-5 years ago where they had one model that was clearly being assembled in some guy's garage. :-) The specs were good though, and they started selling like hotcakes. Given a couple more years I think they (and a few other new companies like Elecraft, and Ten-Tec seems to be hanging on) will start taking a significant bite out of the near-triopoly Kenwood/Icom/Yaesu market that is HF radios.
---Joel
Have been freelance since the mid 1970's. Now getting a bit wrinkly, but manage to stay in work most of the the time. Radio in youth -> electronics -> computing. Currently doing hardware / software design for a client that builds led based highway signs. The biggest ones are 128 pixels high x 192 pixels wide x 2 colours and draw 3-4 Kw power with all the diodes on. Interesting challenges involved w/regard to display timing, update time, self test and other requirements. All the comms is
9600 baud rs485 half duplex, so image data is compressed. Work mainly from own lab these days, but on client site as required.Also have some back burner projects for light aviation using lcd displays. One of those has been so long on the back burner that motorola / freescale eol'd the processor :-(. Am now retargeting to arm 7, as everyone makes them, they are cheap and are more powerfull. Not such an elegant architecture as the Freescale devices though.
So what are you working on ?.
Problem is that there really aren't enough hours in a week to cover all the stuff that looks interesting and we all have to earn a living as well :-)...
Regards,
Chris
That's pretty glacial :-) -- is it some protocol standard that's been around forever?
I'm planning to try out an AVR32 in the not-so-distant future. It seems to have a nice mix of a regular 32-bit CPU's architecture with "DSP lite" additions.
RF design, mostly military and high-end/lower-volume commercial contracts. (I'm a regular old engineer at a small company.) Much of it is still analog, often with some of the simpler digital protocols (e.g., BPSK) tacked on. A lot of what I do is kinda "block diagram" level board design, using MMIC amplifiers, mixers, etc. moreso than discrete transistor-level circuit design. I have done a fair number of filters over time, and have a good-sized handful of switchmode power supply designs under my belt. I also program when needed -- usually low-level stuff like bootloaders and self-test/PC-based-test code. Mostly C/C++ these days, although still a bit of assembly, and I have used Python for a couple of little projects.
It's clear to me that there are people out there who are *much* better than I am at RF design and circuit design (some of them hang out here on SED...). Much of my value seems to be that I have a broader-than-usual set of abilities, even though I'm not an expert in any one particular field. And of course over time I'd like to think my skills have improved; life-long learning is a Good Thing.
---Joel
=20
=20
=20
Could you interest a manufacturer in a larger roadway application device with array like 100 wide by 24 tall (primarily text)? Other constraints similar.
=20
become=20
it=20
was=20
though,=20
think=20
to be=20
near-triopoly=20
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.