Forums

Where do you buy instruments, and who makes 'em?

Started by Tim Wescott December 1, 2011
Tim Wescott wrote:
> I need to get a nice audio signal generator. Something that refers back > to a crystal, instead of a function generator chip. Preferably something > with a DDS and a nice high-accuracy DAC. > > I have something hacked together on proto board that worked astonishingly > well, all things considered -- but it's still hacked together on > protoboard, and only changes frequency with a change of a crystal. > Yesterday I hooked the power up backward, and now it doesn't generate a > steady frequency at all. > > So I'd like to get something with a knob and a case and all that neato > stuff, and if it happens to have a USB port and can be talked to with a > PC running Linux that'd be a minor but nice addition. If possible I'd > like to spend less than $250, but I have no clue what the state of the > market is, so I don't know if $250 is reasonable. > > So -- when you want to get on the internet and order stuff like this, > where do you go? Newark, Mouser and DigiKey all have stuff, but they > primarily sell components. Tucker has stuff, but I've heard comments > that it's expensive. So if you have a place that you like, that doesn't > cost an arm and a leg? > > And -- who makes good inexpensive instruments these days? My Beckman > Industrial signal generator is a cheap thing that makes a wiggly line on > an oscilloscope, and has been doing so reliably since the day I bought it > over 20 years ago. I have no complaints about build quality or how long > it's lasted -- just how well it has always done its job. >
I bought this one: http://www.mastechpowersupply.com/function-generator/20-mhz-digital-function-signal-generator-sfg-2120/prod_58.html The first unit had a defect but the 2nd one they replaced it with works. I do not know if the control software for its USB link would be compatible with Linux though, you'd have to ask. There is a set of commands in the back of the booklet in case you want to hack it together yourself. But the whole booklet has the usual "Chinese brevity" :-) -- Regards, Joerg http://www.analogconsultants.com/
Phil Hobbs a écrit :
> On 12/01/2011 10:30 AM, Tim Wescott wrote: >> I need to get a nice audio signal generator. Something that refers back >> to a crystal, instead of a function generator chip. Preferably something >> with a DDS and a nice high-accuracy DAC. >> >> I have something hacked together on proto board that worked astonishingly >> well, all things considered -- but it's still hacked together on >> protoboard, and only changes frequency with a change of a crystal. >> Yesterday I hooked the power up backward, and now it doesn't generate a >> steady frequency at all. >> >> So I'd like to get something with a knob and a case and all that neato >> stuff, and if it happens to have a USB port and can be talked to with a >> PC running Linux that'd be a minor but nice addition. If possible I'd >> like to spend less than $250, but I have no clue what the state of the >> market is, so I don't know if $250 is reasonable. >> >> So -- when you want to get on the internet and order stuff like this, >> where do you go? Newark, Mouser and DigiKey all have stuff, but they >> primarily sell components. Tucker has stuff, but I've heard comments >> that it's expensive. So if you have a place that you like, that doesn't >> cost an arm and a leg? >> >> And -- who makes good inexpensive instruments these days? My Beckman >> Industrial signal generator is a cheap thing that makes a wiggly line on >> an oscilloscope, and has been doing so reliably since the day I bought it >> over 20 years ago. I have no complaints about build quality or how long >> it's lasted -- just how well it has always done its job. >> > > HP 3325A. I just paid $223 plus $31 shipping for one on eBay. Plus it > goes up to 30 MHz. > > Cheers > > Phil Hobbs >
Yup, nice generator, but at a spec'd -65dBc THD in the audio band it fails the "nice high accuracy DAC" requirement though. IN the same league you have the 3325B and 3324A (which unfortunately lacks a service manual). There's also the 8903A/B audio analyzer with -90dBC THD, but it's a tad more expensive. -- Thanks, Fred.
Tim Wescott wrote:
> I need to get a nice audio signal generator. Something that refers back > to a crystal, instead of a function generator chip. Preferably something > with a DDS and a nice high-accuracy DAC. > > I have something hacked together on proto board that worked astonishingly > well, all things considered -- but it's still hacked together on > protoboard, and only changes frequency with a change of a crystal. > Yesterday I hooked the power up backward, and now it doesn't generate a > steady frequency at all. > > So I'd like to get something with a knob and a case and all that neato > stuff, and if it happens to have a USB port and can be talked to with a > PC running Linux that'd be a minor but nice addition. If possible I'd > like to spend less than $250, but I have no clue what the state of the > market is, so I don't know if $250 is reasonable. > > So -- when you want to get on the internet and order stuff like this, > where do you go? Newark, Mouser and DigiKey all have stuff, but they > primarily sell components. Tucker has stuff, but I've heard comments > that it's expensive. So if you have a place that you like, that doesn't > cost an arm and a leg? > > And -- who makes good inexpensive instruments these days? My Beckman > Industrial signal generator is a cheap thing that makes a wiggly line on > an oscilloscope, and has been doing so reliably since the day I bought it > over 20 years ago. I have no complaints about build quality or how long > it's lasted -- just how well it has always done its job.
This doesn't exactly meet your price range, but it's an interesting new development: http://www.saelig.com/product/PSPC10BIT009.htm There's a lot of neat stuff at Saelig. I'm getting tempted to buy one of their $400 range function generators soon. -- _____________________ Mr.CRC crobcBOGUS@REMOVETHISsbcglobal.net SuSE 10.3 Linux 2.6.22.17
"Mr.CRC" <crobcBOGUS@REMOVETHISsbcglobal.net> wrote:

>Tim Wescott wrote: >> I need to get a nice audio signal generator. Something that refers back >> to a crystal, instead of a function generator chip. Preferably something >> with a DDS and a nice high-accuracy DAC. >> >> I have something hacked together on proto board that worked astonishingly >> well, all things considered -- but it's still hacked together on >> protoboard, and only changes frequency with a change of a crystal. >> Yesterday I hooked the power up backward, and now it doesn't generate a >> steady frequency at all. >> >> So I'd like to get something with a knob and a case and all that neato >> stuff, and if it happens to have a USB port and can be talked to with a >> PC running Linux that'd be a minor but nice addition. If possible I'd >> like to spend less than $250, but I have no clue what the state of the >> market is, so I don't know if $250 is reasonable. >> >> So -- when you want to get on the internet and order stuff like this, >> where do you go? Newark, Mouser and DigiKey all have stuff, but they >> primarily sell components. Tucker has stuff, but I've heard comments >> that it's expensive. So if you have a place that you like, that doesn't >> cost an arm and a leg? >> >> And -- who makes good inexpensive instruments these days? My Beckman >> Industrial signal generator is a cheap thing that makes a wiggly line on >> an oscilloscope, and has been doing so reliably since the day I bought it >> over 20 years ago. I have no complaints about build quality or how long >> it's lasted -- just how well it has always done its job. > > >This doesn't exactly meet your price range, but it's an interesting new >development: > >http://www.saelig.com/product/PSPC10BIT009.htm
I've worked with Picoscope but I'm not impressed. Stability is also an issue. I like this one: http://www.saelig.com/PSBEB100/PSBEB100003.htm This scope has an 8" 800x600 screen. Most entry level scopes (including Tektronix) don't go beyond 320x240. -- Failure does not prove something is impossible, failure simply indicates you are not using the right tools... nico@nctdevpuntnl (punt=.) --------------------------------------------------------------
Nico Coesel wrote:
> "Mr.CRC" <crobcBOGUS@REMOVETHISsbcglobal.net> wrote: >> http://www.saelig.com/product/PSPC10BIT009.htm > > I've worked with Picoscope but I'm not impressed. Stability is also an > issue.
Do you mean software stability? How bad are we talking? What else was wrong with your experience? I've never used them, but have been tempted. The only thing that would draw me though, is something that can't be done with traditional scopes, like very good 16-bit digitization for audio range signal analysis.
> I like this one: > http://www.saelig.com/PSBEB100/PSBEB100003.htm > > This scope has an 8" 800x600 screen. Most entry level scopes > (including Tektronix) don't go beyond 320x240.
Definitely a lot for the money. But how many waveforms/second? -- _____________________ Mr.CRC crobcBOGUS@REMOVETHISsbcglobal.net SuSE 10.3 Linux 2.6.22.17
"Mr.CRC" <crobcBOGUS@REMOVETHISsbcglobal.net> wrote:

>Nico Coesel wrote: >> "Mr.CRC" <crobcBOGUS@REMOVETHISsbcglobal.net> wrote: >>> http://www.saelig.com/product/PSPC10BIT009.htm >> >> I've worked with Picoscope but I'm not impressed. Stability is also an >> issue. > >Do you mean software stability? How bad are we talking? What else was >wrong with your experience? > >I've never used them, but have been tempted. The only thing that would >draw me though, is something that can't be done with traditional scopes, >like very good 16-bit digitization for audio range signal analysis.
IIRC the software freezes sometimes. The input's range is limited to 5V and the menus aren't very intuitive. And if you want to see a lot of weird readings turn on the 'enhanced vertical resolution' (which is bogus BTW because you can't get more bits out of an ADC). If you want to analyze audio you are probably better off with a high end USB sound interface (it isn't a soundcard anymore :-) and a piece of software.
>> I like this one: >> http://www.saelig.com/PSBEB100/PSBEB100003.htm >> >> This scope has an 8" 800x600 screen. Most entry level scopes >> (including Tektronix) don't go beyond 320x240. > >Definitely a lot for the money. But how many waveforms/second?
Is that a meaningful number? I have an older Tek TDS500 series and what I like about it is that it shows several acquisitions and freezes for a short moment after a trigger when in 'auto trigger mode' -- Failure does not prove something is impossible, failure simply indicates you are not using the right tools... nico@nctdevpuntnl (punt=.) --------------------------------------------------------------
On Thursday, December 1, 2011 7:30:48 AM UTC-8, Tim Wescott wrote:
> I need to get a nice audio signal generator. Something that refers back > to a crystal, instead of a function generator chip. Preferably something > with a DDS and a nice high-accuracy DAC.
> So I'd like to get something with a knob and a case and all that neato > stuff, and if it happens to have a USB port ...
Well, there's always the mass-produced ones. Ipod nano can play two output channels of any kind of audio you can imagine and program. Tones, sine burst, noise burst, FM sweeps... just buy a CD test disk to get started with audio signals. No knob, though, you gotta use the color touchscreen.
On 12/1/2011 9:30 AM, Tim Wescott wrote:
> I need to get a nice audio signal generator. Something that refers back > to a crystal, instead of a function generator chip. Preferably something > with a DDS and a nice high-accuracy DAC.
This is my third attempt to post this, I've had newsgroup access problems, they seem to have self corrected this morning. I emailed it to Tim, but others may be interested. Here's a board built in Australia. Seems expensive compared to bare boards others have posted, $145 but maybe it has bells and whistles you'll like. DC to 940Mhz http://www.softmark.com.au/page37.html Homepage; http://www.softmark.com.au/ Mikek
"amdx"  wrote in message =
news:7f051$4ede108c$18ec6dd7$21610@KNOLOGY.NET...

> Here's a board built in Australia. > Seems expensive compared to bare boards others have posted, > $145 but maybe it has bells and whistles you'll like. > DC to 940Mhz
> http://www.softmark.com.au/page37.html
> Homepage;
> http://www.softmark.com.au/
They have some good stuff. It is a bit pricey but not bad if the quality = is=20 good. I'm designing a three-phase USB signal generator. It will = basically be=20 an arbitrary waveform generator with three channels, using EEPROM or = SRAM=20 and a quad DAC. It will be limited to power line frequencies if I use = the=20 PIC crystal oscillator to drive the counter directly, but much higher=20 frequencies can be obtained if I use a VCO and/or a PLL. It's a "back=20 burner" project but I think it may be useful. Maybe these guys would be=20 interested in adding it to their products? Paul=20
On 12/6/2011 6:54 AM, amdx wrote:

> I emailed it to Tim, but others may be interested. > > Here's a board built in Australia. > Seems expensive compared to bare boards others have posted, $145 > but maybe it has bells and whistles you'll like. > DC to 940Mhz
That's the attenuator specs. The synthesizer only goes to 85MHz.
> http://www.softmark.com.au/page37.html > > Homepage; > > http://www.softmark.com.au/ > > Mikek