Re: proper way to connect single ended to differential circuits
Hello Andy,In the attached folder there is the united circuit where the PID and the driver I chose.
I grounded one of the input legs of the differential driver.
The driver is desscribed in the link.
You said that "? A transformer is one pretty good way, but it is AC only.? A simple inverter is another"
My driver is suppose to pass a PID controller behavior. What device you reccomend to connect the two?
Thanks.
https://www.analog.com/cn/resources/technical-articles/adsl-line-driver-receiver-design-guide-part-two.html
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Re: inexpensive 600/600 ohm AF transformers
These were new old stock and I didn't have to desolder a bunch of transformers.
I'm as cheap as the next guy, but, at 73 I have to balance the value of my time on this side of the grass against the cost of just buying something and finishing a project that has been hanging on some design changes my friend couldn't decide on, so I decided for him, he can have someone else modify my design if he wants.
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Re: inexpensive 600/600 ohm AF transformers
Such transformers, with, and without CT, can be recovered from old computer modems add-in cards. ? Nuno T. ?
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From: [email protected] [mailto:[email protected]] On Behalf Of wn4isx via groups.io
Sent: 22 February 2025 22:52
To: [email protected]
Subject: [electronics101] inexpensive 600/600 ohm AF transformers ? First, I have no financial stake in Electronic Goldmine, I'm just a satisfied customer. ? I needed some transformers for a special project and Electronic Goldmine started offering these. ?Microtran Pico Transformer PM34-M Miniature 600 Ohm C.T. to 600 Ohm C.T. 50mW Rating"Microtran Pico transformer type PM34-M is a miniature fully encapsulated 50mW rated 600 Ohm C.T. to 600 Ohm C.T. transformer. Frequency response is ±2db 300Hz to 100KHz. Has 6 full length leads. Size only 0.3" x 0.4" x 0.425" tall. New" at ? https://theelectronicgoldmine.com/products/g28678 ? Full specs can be found here https://www.technicalaudio.com/pdf/MicroTran/Microtran_miniature_transformers_catalog_1974.pdf ? Electronic Goldmine offers surplus, new old stock, components and probably doesn't have oodles of these. ? 60Hz appears be just over -3dB. YMWV depending on your system. Short pulses of 1 cycle or 1kHz show minimum ringing. ? These could be ideal for coupling a computer to a ham/shortwave radio, PA, or other interface needs. ? ? -- Nuno T.
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Re: proper way to connect single ended to differential circuits
On Sun, Feb 23, 2025 at 07:41 AM, john23 wrote:
Hello , I have a single ended PID and a vccs driver (differential )
Not enough information.
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Depending on the differential input circuit, and on its CMRR, it may accept single-ended inputs directly.? Apply signal and ground to the differential input pins.
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There are ways to actually convert a single-ended signal into a differential pair, should that be necessary.? A transformer is one pretty good way, but it is AC only.? A simple inverter is another.? You can get more fancy about them, but these are simplest.
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Since your "diff" input circuit drives a transformer primary, it probably has excellent CMRR.
?
Andy
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Re: inexpensive 600/600 ohm AF transformers
I gave quite a few suitable transformers of mixed heritage.
But, I was building a project for a friend and decided using the same transformers would make life easier for someone else down the line, probably long after I'm gone. I even included 4 spare transformers.
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Re: inexpensive 600/600 ohm AF transformers
On Saturday 22 February 2025 05:52:07 pm wn4isx via groups.io wrote: First, I have no financial stake in Electronic Goldmine, I'm just a satisfied customer. I got that when you brought it up before. I needed some transformers for a special project and Electronic Goldmine started offering these.
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Microtran Pico Transformer PM34-M Miniature 600 Ohm C.T. to 600 Ohm C.T. 50mW Rating
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" Microtran Pico transformer type PM34-M is a miniature fully encapsulated 50mW rated 600 Ohm C.T. to 600 Ohm C.T. transformer. Frequency response is ±2db 300Hz to 100KHz. Has 6 full length leads. Size only 0.3" x 0.4" x 0.425" tall. New " Not bad for communications gear, but for more general audio uses that lower end of the frequency response is pretty pitiful. Electronic Goldmine offers surplus, new old stock, components and probably doesn't have oodles of these. I did take a look at their site, lots of interesting junk there. But I really need to deal with the junk I have here first, I think... 60Hz appears be just over -3dB. YMWV depending on your system. Short pulses of 1 cycle or 1kHz show minimum ringing.
These could be ideal for coupling a computer to a ham/shortwave radio, PA, or other interface needs. Noted. -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin
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proper way to connect single ended to differential circuits
Hello , I have a single ended PID and a vccs driver (differential )
What is the best way to connect the two, so the PID output will be driver input?
Thanks.
/g/electronics101/photo/296358/3889904?p=Created%2C%2C%2C20%2C2%2C0%2C0
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inexpensive 600/600 ohm AF transformers
First, I have no financial stake in Electronic Goldmine, I'm just a satisfied customer.
?
I needed some transformers for a special project and Electronic Goldmine started offering these.
?Microtran Pico Transformer PM34-M Miniature 600 Ohm C.T. to 600 Ohm C.T. 50mW Rating
"Microtran Pico transformer type PM34-M is a miniature fully encapsulated 50mW rated 600 Ohm C.T. to 600 Ohm C.T. transformer. Frequency response is ±2db 300Hz to 100KHz. Has 6 full length leads. Size only 0.3" x 0.4" x 0.425" tall. New"
at
?
https://theelectronicgoldmine.com/products/g28678
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Full specs can be found here
https://www.technicalaudio.com/pdf/MicroTran/Microtran_miniature_transformers_catalog_1974.pdf
?
Electronic Goldmine offers surplus, new old stock, components and probably doesn't have oodles of these.
?
60Hz appears be just over -3dB. YMWV depending on your system. Short pulses of 1 cycle or 1kHz show minimum ringing.
?
These could be ideal for coupling a computer to a ham/shortwave radio, PA, or other interface needs.
?
?
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Re: CTI OCXO type OSC5A2B02
On Saturday 15 February 2025 11:26:30 am wn4isx via groups.io wrote: I've used these in a variety of projects and never been dissapointed. I don't know specific numbers offhand, but I have a whole pile of those "canned" oscillators in various frequencies. The kind where you plug 'em into an IC socket. I assume that two opposite corners are for +5v and ground and one of the two remaining pins is the output. I'm also assuming that most of these put out a square wave, though I haven't checked. What kind of things do you find those useful for? Most of the ones I have are NOS, but I've pulled a few off of MBs and ISA video cards. -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin
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Re: poor/distorted tx audio
On Friday 14 February 2025 04:43:42 pm wn4isx via groups.io wrote: I typically place a 10k metal film resistor across both primary and secondary to inhibit ringing. These values worked for me but might need to be tweaked depending on your setup. I don't recall what value my friend suggested, and it was a *long* time ago... Ringing can be extremely difficult to see on a standard, phosphor, scope, a DSO or storage phosphor scope might be required. And you'll probably never hear it because the ringing only lasts a cycle before rapidly fading to nothing. I used to see it all the time with my Tek 2246 when troubleshooting stuff like the c64. Probably because I was using the longer ground lead on my probe. It was a surprise to me that the darn thing worked at all with how dirty those signals were. This can be a real killer for modern RF data formats, I have yet to play with any of those. Hell, with no antennas up and only having one in the cars I haven't been on the air in ages. Never mind getting into all of that stuff. Oh I never meant to imply that you needed a Jensen shielded transformer, in most cases you won't, but there are ham shacks with enough magnetic field strength only a premium transformer will work and they are obscenely expensive. Hence, the "rob a bank" snark.
A quick test, connect the transformer you plan to use to a battery operated amplifier, a cassette deck will do. Use high quality mini-coax (RG-174) with good connectors and sniff for 60Hz +harmonic hum. If you have a lot, you have a problem, now I can't tell you what a lot might be because I won't have your transformer, amplifier etc. I have the coil from a 12 or 24V DC relay that I've encased in expoxy with 5 feet of RG-174. I use it for hum surveys for friends, I have an idea what is OK and what isn't but it is far from scientific. I'll keep that in mind if I ever get any reports of hum or similar on my signal, if I ever get back on the air again. -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin
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Re: poor/distorted tx audio
On Friday 14 February 2025 04:32:40 pm wn4isx via groups.io wrote: On Fri, Feb 14, 2025 at 01:55 PM, Roy J. Tellason, Sr. wrote:
It's interesting that he shows different dc resistance for primary and
secondary, I'd have thought that they'd both be the same.
The winding are separate, one inside the other so it has shorter turns and a lower resistance, the other is outside and has longer turns so it has a higher resistance. Okay, that makes sense... This data can be used as your friend, feed your output signal to the higher resistance and take your signal from the lower, this way the lower resistance is shielded to some degree by the outer winding and will >probably< pick up less stray noise. I wouldn't have thought to do that, either. I'll have to check the ones I salvaged, and see what they measure. -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin
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Re: CTI OCXO type OSC5A2B02
On Sat, Feb 15, 2025 at 09:42 AM, Sam Reaves wrote:
I don't remember if they are square wave or sine wave but you could filter the square to a sine if needed.
Epson offers sine, triangle and square wave, though not all waveforms are available on all models.
They have reasonably low phase noise, I wouldn't want to use one for a VHF digital data mode, but for most applications they are very good.
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Turn around time is 1 to 2 weeks.
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I've used these in a variety of projects and never been dissapointed.
?
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Re: CTI OCXO type OSC5A2B02
The crystal in these has a very special cut (SC? IIRC) that has a temperature curve that is very flat in the operation area as compared to the commonly available AT cut. The parabolic curve slope broadens out as compared to the AT. This way the oven temperature control does not have to control the temperature quite as precisely to achieve?the desired results. Perhaps if you could get the appropriate crystal and knew the?oven operating temperature?it could be made to work. They are outstanding 10MHz OCXO's?if?you don't get one where the crystal has aged out of EFC range.
There are programmable oscillators available from Digi-Key that they will program for you to a specific frequency. I think SITime makes them. I don't remember if they are square wave or sine wave but you could filter the square to a sine if needed.
Sam
Sam
Sam Reaves
ARS W3OHM
Owner / Moderator of: LeCroy Owners Group on Groups.io
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A friend tried this and the answer is .... Nope.
Opening the sealed metal case is a challenge, Joey destroyed 4 before he succeeded with number 5.
Everything inside is supper small surface mount, including the crystal. And they don't use lead-tin solder, probably used silver solder.
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What frequency do you need?
Is there anyway to get it with a divide by chain or device by chain with a PLL with divide by chain for multiplication.
For instance, I needed 60Hz, so I divided down to 20Hz, used a PLL with a divide by 6 in the loop to multiply by 6 to get 120, followed with a divide by 2 to get 60Hz.
?
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Re: CTI OCXO type OSC5A2B02
A friend tried this and the answer is .... Nope.
Opening the sealed metal case is a challenge, Joey destroyed 4 before he succeeded with number 5.
Everything inside is supper small surface mount, including the crystal. And they don't use lead-tin solder, probably used silver solder.
?
What frequency do you need?
Is there anyway to get it with a divide by chain or device by chain with a PLL with divide by chain for multiplication.
For instance, I needed 60Hz, so I divided down to 20Hz, used a PLL with a divide by 6 in the loop to multiply by 6 to get 120, followed with a divide by 2 to get 60Hz.
?
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does anyone know if these ( cCTI OCXO type OSC5A2B02_can work at different frequencys if the internal crystal is swapped for a different freq item?.
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Re: poor/distorted tx audio
has anyone done a carrier point alignment on the 707/,its vr 3001 and tc 3004 adjustments on the af board,i am having distorted tx audio reports,is there an easy way to adjust?.
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Re: poor/distorted tx audio
Those Bell systems transformers were a good size. I was designing early SMT components to be able to shrink pager size. Try winding #44 magnet wire on a 1mm, 40 mil, diameter ferrite rod and solder the wires to a ceramic substrate 0.1x0.1 inch 2.5mm. Or 5 turns bifilar wound on a 0.1” toroid with proper impedance at 450 MHz on 4 x 4mm base. The amazing part:? It was all done by hand in Haiti about 50 years ago.? It was safe in Haiti at that time.? I did not have to worry about security. Bertho ?
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From: [email protected] <[email protected]> On Behalf Of wn4isx via groups.io
Sent: 14 February, 2025 18:26
To: [email protected]
Subject: Re: [electronics101] poor/distorted tx audio? I love bifilar and trifilar windings but modem and very few audio transformers use that format. I've wound special bifilar winding for a receiver for whistlers, RF 1~3kHz. Didn't work any better then a normal transformer. For RF they are the only way to go. Bettho, sir, you have lead an interesting life. I can't imagine the difficulty of training non native English speakers to do technical work. Hell it was difficult enough to work with native born Americans as student workers to do some of the simplest tasks. There was one kid I sort of wished would fall off a 6 story building. Yea the paperwork would have been daunting but a nightmare "worker" would have been gone. The worst were the EE students, they thought they knew enough to not listen to directions in our TV facility. I considered strangulation with 75 ohm coax a time or two.... They couldn't understand why NTSC black burst timing cables had to be 80M/4 long..... [3.58 is ~80 meters] You calculate the length, apply violocity factor, cut the cable a foot long and trim back an inch at a time with a push on BNC. God I hated making those cables. Oddly enough the English and Philosophy majors actually listened and did as they were told.
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Re: poor/distorted tx audio
I love bifilar and trifilar windings but modem and very few audio transformers use that format.
I've wound special bifilar winding for a receiver for whistlers, RF 1~3kHz. Didn't work any better then a normal transformer.
?
For RF they are the only way to go.
?
Bettho, sir, you have lead an interesting life.
I can't imagine the difficulty of training non native English speakers to do technical work.
Hell it was difficult enough to work with native born Americans as student workers to do some of the simplest tasks. There was one kid I sort of wished would fall off a 6 story building. Yea the paperwork would have been daunting but a nightmare "worker" would have been gone.
The worst were the EE students, they thought they knew enough to not listen to directions in our TV facility.
I considered strangulation with 75 ohm coax a time or two....
They couldn't understand why NTSC black burst timing cables had to be 80M/4 long.....
[3.58 is ~80 meters] You calculate the length, apply violocity factor, cut the cable a foot long and trim back an inch at a time with a push on BNC. God I hated making those cables.
?
Oddly enough the English and Philosophy majors actually listened and did as they were told.
?
?
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Re: poor/distorted tx audio
Telephone company line I-O transformers: Your comments below reminded me of setting up production and custom automated test equipment for high volume production of the transformers.? The were ferrite potcores, about an inch in diameter. They had a bi-filar wound line input side, an equipment side winding, and an extra monitoring winding. Each transformer had to be tested for 14 variables: For example, turn ratio between the windings, balances, winding resistances , frequency response, insertion loss, and a high pot test. All the test equipment ran on HP-IL with custom modules and DVMs.? We made thousands per week in Dominican Republic.? That was about 35 years ago. Bertho ?
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From: [email protected] <[email protected]> On Behalf Of wn4isx via groups.io
Sent: 14 February, 2025 16:33
To: [email protected]
Subject: Re: [electronics101] poor/distorted tx audio? On Fri, Feb 14, 2025 at 01:55 PM, Roy J. Tellason, Sr. wrote: It's interesting that he shows different dc resistance for primary and secondary, I'd have thought that they'd both be the same.
The winding are separate, one inside the other so it has shorter turns and a lower resistance, the other is outside and has longer turns so it has a higher resistance. This isn't theory, my Bell Systems 600:600 show the same effect and are labeled as 600 ohms and XYZ DC resistance, the other is 600 ohms and ABC resistance. The side label says the XYZ winding must face the central plant. I have 4 and they are probably 80+ years old and each weigh 4 or 5 pounds. They are packed away so the XYZ and ABC resistance. This data can be used as your friend, feed your output signal to the higher resistance and take your signal from the lower, this way the lower resistance is shielded to some degree by the outer winding and will >probably< pick up less stray noise.
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Re: poor/distorted tx audio
Forgot to mention ringing, if you are dealing with square wave, or very short bursts of AF, say 10~20 cycles of 1kHz, ringing can be a problem. I don't know why it is an issue in some transformers but not others.
I typically place a 10k metal film resistor across both primary and secondary to inhibit ringing. These values worked for me but might need to be tweaked depending on your setup.
?
Ringing can be extremely difficult to see on a standard, phosphor, scope, a DSO or storage phosphor scope might be required. And you'll probably never hear it because the ringing only lasts a cycle before rapidly fading to nothing.
?
This can be a real killer for modern RF data formats,
?
Oh I never meant to imply that you needed a Jensen shielded transformer, in most cases you won't, but there are ham shacks with enough magnetic field strength only a premium transformer will work and they are obscenely expensive. Hence, the "rob a bank" snark.
?
A quick test, connect the transformer you plan to use to a battery operated amplifier, a cassette deck will do. Use high quality mini-coax (RG-174) with good connectors and sniff for 60Hz +harmonic hum. If you have a lot, you have a problem, now I can't tell you what a lot might be because I won't have your transformer, amplifier etc. I have the coil from a 12 or 24V DC relay that I've encased in expoxy with 5 feet of RG-174. I use it for hum surveys for friends, I have an idea what is OK and what isn't but it is far from scientific.?
Now if I had 2 30V batteries, I could use my HP AF micro to 100V meter to take actual readings, but I have no idea what type relay my coil came from, it was in a friend's junk box and I didn't pay attention to anything except the dark phillips screw holding the coil in place. It was a pain to remove. I tossed the rest of the relay in his recycle bin.
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Sam Reaves
Bertho