On Dec 12, 6:54=A0pm, "Michael A. Terrell" <mike.terr...@earthlink.net> wrote:> George Herold wrote: > > > *Teachscope, sold for a few hundred and put out 12 different 'signals' > > that the students would have to 'go find' with a 'scope. =A0I wish > > someone would make the current day equivalent out of a uC. > > =A0 =A0Have you ever tried a cheap DDS? =A0Here is a module with an AD 89=50> for under $8. It can be driven by a small processor, and Analog Devices > has a demo program with a simple parallel port interface to play with. > They offer sample code for the 8051, (I think. It's been a while since I > looked) > > http://www.ebay.com/itm/280840956721which is 0 to 40 MHz, and can have > the outrput level set by software.Yeah the cost is all in the dam#, box, switch, connector, power supply... I need someone to make thousands of 'em. George H.
are all the function generators gone?
Started by ●December 12, 2012
Reply by ●December 12, 20122012-12-12
Reply by ●December 12, 20122012-12-12
On Dec 12, 7:03=A0pm, Jim Thompson <To-Email-Use-The-Envelope-I...@On-My- Web-Site.com> wrote:> On Wed, 12 Dec 2012 15:14:48 -0800 (PST), George Herold > > > > > > <gher...@teachspin.com> wrote: > >On Dec 12, 5:51 pm, John Larkin <jlar...@highlandtechnology.com> > >wrote: > >> I'm being asked to make some replacement FSK modems for a system I > >> designed about 30 years ago... not much money to be made, really just > >> a charity job. I originally used the XR2206 as the transmit > >> oscillator, and they are gone. Well, Mouser has one piece for $83. > > >> MAX038 is gone, too. Jameco has some 2206 DIPs, which I could scoop > >> up, I guess. > > >Do you need a lot? =A0We've got several tubes left over from a > >discontinued > >gizmo*. > > >> Anybody know of a classic analog sinewave generator chip? A uP and DDS > >> would be a lot of hassle. And I'd like to be able to set the > >> mark/space frequencies with pots. > > >> I guess I could make a triangle oscillator and sort of bend it into a > >> sine wave. THD wouldn't matter much. > > >You could use a clocked 4017 with different R's into a opamp summing > >junction. =A0(Phil or James suggested it a while back.) =A0With ten step=s> >you move most of the 'distortion' out to the 9th and 11th harmonic. > > >George H. > > >*Teachscope, sold for a few hundred and put out 12 different 'signals' > >that the students would have to 'go find' with a 'scope. =A0I wish > >someone would make the current day equivalent out of a uC. > > >> The receive direction is easy. I'll use my almost-famous dual tach > >> circuit > > >>https://dl.dropbox.com/u/53724080/Circuits/DoubleTach.jpg > > >> with a decent output filter and a comparator. > > >> -- > > >> John Larkin Highland Technology, Inc > > >> jlarkin at highlandtechnology dot comhttp://www.highlandtechnology.com > > [snip non-compliant sig] > > You can easily make a modem from active filter structures. =A0That's > what I used for the OmniComp/GenRad international-frequency-selectable > modem circa 1981-82... dirt cheap but very accurate. > > The discriminator was patented... > > =A0 =A0 =A0http://www.analog-innovations.com/SED/Pat-4472816.pdfNeat, what was the mixer? (an XOR?) George H.> > Much better performance in the presence of noise than the TI digital > chips of that era. =A0(I'll have to dig thru my lab notes, but I may > even have used an LM324 :-) > > I'm trying to remember now, but I most likely used something like this > for the transmitter... > > =A0http://www.analog-innovations.com/SED/Sedra-Espinosa-Oscillator.pdf > > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 ==A0 =A0 ...Jim Thompson> -- > | James E.Thompson, CTO =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 ==A0 =A0| =A0 =A0mens =A0 =A0 |> | Analog Innovations, Inc. =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 ==A0 | =A0 =A0 et =A0 =A0 =A0|> | Analog/Mixed-Signal ASIC's and Discrete Systems =A0| =A0 =A0manus =A0 ==A0|> | Phoenix, Arizona =A085048 =A0 =A0Skype: Contacts Only =A0| =A0 =A0 =A0 ==A0 =A0 =A0 |> | Voice:(480)460-2350 =A0Fax: Available upon request | =A0Brass Rat =A0| > | E-mail Icon athttp://www.analog-innovations.com| =A0 =A01962 =A0 =A0 | > > I love to cook with wine. =A0 =A0 Sometimes I even put it in the food.- H=ide quoted text -> > - Show quoted text -
Reply by ●December 12, 20122012-12-12
On Wed, 12 Dec 2012 17:49:40 -0800 (PST), George Herold <gherold@teachspin.com> wrote:>On Dec 12, 7:03�pm, Jim Thompson <To-Email-Use-The-Envelope-I...@On-My- >Web-Site.com> wrote: >> On Wed, 12 Dec 2012 15:14:48 -0800 (PST), George Herold >> >> >> >> >> >> <gher...@teachspin.com> wrote: >> >On Dec 12, 5:51 pm, John Larkin <jlar...@highlandtechnology.com> >> >wrote: >> >> I'm being asked to make some replacement FSK modems for a system I >> >> designed about 30 years ago... not much money to be made, really just >> >> a charity job. I originally used the XR2206 as the transmit >> >> oscillator, and they are gone. Well, Mouser has one piece for $83. >> >> >> MAX038 is gone, too. Jameco has some 2206 DIPs, which I could scoop >> >> up, I guess. >> >> >Do you need a lot? �We've got several tubes left over from a >> >discontinued >> >gizmo*. >> >> >> Anybody know of a classic analog sinewave generator chip? A uP and DDS >> >> would be a lot of hassle. And I'd like to be able to set the >> >> mark/space frequencies with pots. >> >> >> I guess I could make a triangle oscillator and sort of bend it into a >> >> sine wave. THD wouldn't matter much. >> >> >You could use a clocked 4017 with different R's into a opamp summing >> >junction. �(Phil or James suggested it a while back.) �With ten steps >> >you move most of the 'distortion' out to the 9th and 11th harmonic. >> >> >George H. >> >> >*Teachscope, sold for a few hundred and put out 12 different 'signals' >> >that the students would have to 'go find' with a 'scope. �I wish >> >someone would make the current day equivalent out of a uC. >> >> >> The receive direction is easy. I'll use my almost-famous dual tach >> >> circuit >> >> >>https://dl.dropbox.com/u/53724080/Circuits/DoubleTach.jpg >> >> >> with a decent output filter and a comparator. >> >> >> -- >> >> >> John Larkin Highland Technology, Inc >> >> >> jlarkin at highlandtechnology dot comhttp://www.highlandtechnology.com >> >> [snip non-compliant sig] >> >> You can easily make a modem from active filter structures. �That's >> what I used for the OmniComp/GenRad international-frequency-selectable >> modem circa 1981-82... dirt cheap but very accurate. >> >> The discriminator was patented... >> >> � � �http://www.analog-innovations.com/SED/Pat-4472816.pdf > >Neat, what was the mixer? (an XOR?)Direct. It's audio, 1200/2200> >George H. >> >> Much better performance in the presence of noise than the TI digital >> chips of that era. �(I'll have to dig thru my lab notes, but I may >> even have used an LM324 :-) >> >> I'm trying to remember now, but I most likely used something like this >> for the transmitter... >> >> �http://www.analog-innovations.com/SED/Sedra-Espinosa-Oscillator.pdf >> >> � � � � � � � � � � � � � � � � � � � � ...Jim Thompson[snip] ...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 | I love to cook with wine. Sometimes I even put it in the food.
Reply by ●December 12, 20122012-12-12
On Wed, 12 Dec 2012 14:51:48 -0800, John Larkin <jlarkin@highlandtechnology.com> wrote:>I originally used the XR2206 as the transmit >oscillator, and they are gone. Well, Mouser has one piece for $83. >MAX038 is gone, too. Jameco has some 2206 DIPs, which I could scoop >up, I guess.They're available on eBay from a variety of vendors: <http://www.ebay.com/sch/i.html?_trksid=p3872.m570.l1313&_nkw=xr2206> -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
Reply by ●December 13, 20122012-12-13
"John Larkin" <jlarkin@highlandtechnology.com> wrote in message news:cs1ic8dolr2vbd11j13ebiprklfh0asgq0@4ax.com...> > I'm being asked to make some replacement FSK modems for a system I > designed about 30 years ago... not much money to be made, really just > a charity job. I originally used the XR2206 as the transmit > oscillator, and they are gone. Well, Mouser has one piece for $83. > MAX038 is gone, too. Jameco has some 2206 DIPs, which I could scoop > up, I guess. > > Anybody know of a classic analog sinewave generator chip? A uP and DDS > would be a lot of hassle. And I'd like to be able to set the > mark/space frequencies with pots. > > I guess I could make a triangle oscillator and sort of bend it into a > sine wave. THD wouldn't matter much. > > The receive direction is easy. I'll use my almost-famous dual tach > circuit > > https://dl.dropbox.com/u/53724080/Circuits/DoubleTach.jpg > > with a decent output filter and a comparator. > > > >What about the XR2211? <http://www.exar.com/communications/timing/voltage-controlled-oscillator-vco/xr2211a> Cheers
Reply by ●December 13, 20122012-12-13
We did a Bell 103 for a fallback using a coordic to generate the CPFSK. Trivial if you know the algorithm. Demod was done computing the arcsin, again with a coordic, unwraping the phase, then doing a LMS line fit to get the incoming frequency. The slope of the phase is the frequency. This was circa 1985.
Reply by ●December 13, 20122012-12-13
On Thu, 13 Dec 2012 00:32:20 -0500, "Martin Riddle" <martin_rid@verizon.net> wrote:> >"John Larkin" <jlarkin@highlandtechnology.com> wrote in message >news:cs1ic8dolr2vbd11j13ebiprklfh0asgq0@4ax.com... >> >> I'm being asked to make some replacement FSK modems for a system I >> designed about 30 years ago... not much money to be made, really just >> a charity job. I originally used the XR2206 as the transmit >> oscillator, and they are gone. Well, Mouser has one piece for $83. >> MAX038 is gone, too. Jameco has some 2206 DIPs, which I could scoop >> up, I guess. >> >> Anybody know of a classic analog sinewave generator chip? A uP and DDS >> would be a lot of hassle. And I'd like to be able to set the >> mark/space frequencies with pots. >> >> I guess I could make a triangle oscillator and sort of bend it into a >> sine wave. THD wouldn't matter much. >> >> The receive direction is easy. I'll use my almost-famous dual tach >> circuit >> >> https://dl.dropbox.com/u/53724080/Circuits/DoubleTach.jpg >> >> with a decent output filter and a comparator. >> >> >> >> > >What about the XR2211? > ><http://www.exar.com/communications/timing/voltage-controlled-oscillator-vco/xr2211a> > >Cheers >I can do the receiver with my tach circuit, probably a better FSK detector than a PLL. It looks like there are lots of 2206's on ebay, from vendors with good feedback, so maybe I'll get a lifetime supply of them for the transmitters. Thanks to the guys for the tip. Interestingly, the old Bell 202 protocol (1200/2200 Hz FSK) is still used in industrial (like HART) and RF applications, and several people sell modems. But most/all use a DSP modem chip, which don't like my somewhat-off frequencies. Old analog modems work. I designed the systems in question about 30 years ago. The remote units have a software transmit-side UART+Modem (MC6802 with a 2708 1kbyte eprom) that transmits at 1200 baud with FSK frequencies 1200 and 2400 Hz, sort of synchronous FSK. That was really easy to do in software, but it freaks out the DSP modem chips. I could make my own triangle generator and sine shaper with a few standard ICs, but the 2206 does it all. -- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
Reply by ●December 13, 20122012-12-13
On Wed, 12 Dec 2012 17:49:40 -0800 (PST), George Herold <gherold@teachspin.com> wrote:>On Dec 12, 7:03�pm, Jim Thompson <To-Email-Use-The-Envelope-I...@On-My- >Web-Site.com> wrote: >> On Wed, 12 Dec 2012 15:14:48 -0800 (PST), George Herold >> >> >> >> >> >> <gher...@teachspin.com> wrote: >> >On Dec 12, 5:51 pm, John Larkin <jlar...@highlandtechnology.com> >> >wrote: >> >> I'm being asked to make some replacement FSK modems for a system I >> >> designed about 30 years ago... not much money to be made, really just >> >> a charity job. I originally used the XR2206 as the transmit >> >> oscillator, and they are gone. Well, Mouser has one piece for $83. >> >> >> MAX038 is gone, too. Jameco has some 2206 DIPs, which I could scoop >> >> up, I guess. >> >> >Do you need a lot? �We've got several tubes left over from a >> >discontinued >> >gizmo*. >> >> >> Anybody know of a classic analog sinewave generator chip? A uP and DDS >> >> would be a lot of hassle. And I'd like to be able to set the >> >> mark/space frequencies with pots. >> >> >> I guess I could make a triangle oscillator and sort of bend it into a >> >> sine wave. THD wouldn't matter much. >> >> >You could use a clocked 4017 with different R's into a opamp summing >> >junction. �(Phil or James suggested it a while back.) �With ten steps >> >you move most of the 'distortion' out to the 9th and 11th harmonic. >> >> >George H. >> >> >*Teachscope, sold for a few hundred and put out 12 different 'signals' >> >that the students would have to 'go find' with a 'scope. �I wish >> >someone would make the current day equivalent out of a uC. >> >> >> The receive direction is easy. I'll use my almost-famous dual tach >> >> circuit >> >> >>https://dl.dropbox.com/u/53724080/Circuits/DoubleTach.jpg >> >> >> with a decent output filter and a comparator. >> >> >> -- >> >> >> John Larkin Highland Technology, Inc >> >> >> jlarkin at highlandtechnology dot comhttp://www.highlandtechnology.com >> >> [snip non-compliant sig] >> >> You can easily make a modem from active filter structures. �That's >> what I used for the OmniComp/GenRad international-frequency-selectable >> modem circa 1981-82... dirt cheap but very accurate. >> >> The discriminator was patented... >> >> � � �http://www.analog-innovations.com/SED/Pat-4472816.pdf > >Neat, what was the mixer? (an XOR?)I did essentially the same thing about 10 years prior, but used an RLC as the phase shifter, technically a very peaky lowpass filter. A jfet or (later) a cmos XOR gate was the mixer which fed the output filter, also an LC thing. This was for a series of narrowband FSK modems for pipeline and electric utility supervisory systems. The tricky part was the input bandpass filter. It had to be tight, because many modems shared a leased phone line. And it had to have flat delay vs frequency. One of my more mathematical engineers came up with some clever elliptical filters where the notches also did the delay equalization. -- John Larkin Highland Technology, Inc jlarkin at highlandtechnology dot com http://www.highlandtechnology.com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser drivers and controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation
Reply by ●December 14, 20122012-12-14
On Thu, 13 Dec 2012 08:51:48 +1000, John Larkin <jlarkin@highlandtechnology.com> wrote:> > I'm being asked to make some replacement FSK modems for a system I > designed about 30 years ago... not much money to be made, really just > a charity job. I originally used the XR2206 as the transmit > oscillator, and they are gone. Well, Mouser has one piece for $83. > MAX038 is gone, too. Jameco has some 2206 DIPs, which I could scoop > up, I guess. > > Anybody know of a classic analog sinewave generator chip? A uP and DDS > would be a lot of hassle. And I'd like to be able to set the > mark/space frequencies with pots. > > I guess I could make a triangle oscillator and sort of bend it into a > sine wave. THD wouldn't matter much. > > The receive direction is easy. I'll use my almost-famous dual tach > circuit > > https://dl.dropbox.com/u/53724080/Circuits/DoubleTach.jpg > > with a decent output filter and a comparator. > > > > > >XR2206 $4.95 - I know it is not your favorite type of supplier but since there is no profit in this job ... http://www.futurlec.com.au/test13.jsp?category=ICOTHERS&category_title=Others&main_menu=IC&sub_menu=ICOTHERS
Reply by ●December 14, 20122012-12-14
