Author Topic: Conversion of 500MHz TDS744A to 1GHz TDS784A  (Read 34685 times)

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Offline Jay_Diddy_B

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Re: Conversion of 500MHz TDS744A to 1GHz TDS784A
« Reply #25 on: January 20, 2016, 10:32:30 am »
I would like to capture my TDS744A scope screen display image and store it on my computer for reference. What is the TDS7xx hardware/software setup you all are using to post these perfect scope screen images?
Thanks, Tom

The images were made by printing or plotting to the floppy drive in the scope.

You have to configure the plotting in the 'UTILITY' menu and then plot with the HARDCOPY key.

Regards,

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Offline tford

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Re: Conversion of 500MHz TDS744A to 1GHz TDS784A
« Reply #26 on: January 21, 2016, 10:35:13 am »
Got it. I'll likely have to purchase a USB 3.5" floppy disk drive for my PC, only about $15. I was hoping to use the rear scope centronics or serial connector and go directly into my PC, but those options are limited. 
Thanks,
Tom
 

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Re: Conversion of 500MHz TDS744A to 1GHz TDS784A
« Reply #27 on: January 22, 2016, 12:36:03 am »
Got it. I'll likely have to purchase a USB 3.5" floppy disk drive for my PC, only about $15. I was hoping to use the rear scope centronics or serial connector and go directly into my PC, but those options are limited. 
Thanks,
Tom

You can use the GPIB interface if you use John Miles' excellent 7470 plotter.
http://www.ke5fx.com/gpib/7470.htm

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Offline cncjerry

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Re: Conversion of 500MHz TDS744A to 1GHz TDS784A
« Reply #28 on: March 22, 2016, 02:19:13 am »
Get the plotting software mentioned earlier from John Miles, www.ke5fx.com.

Also, I am starting to think the distortion we discussed a while back was caused by the poster's scope seeing the 2nd harmonic, or some of it, in 4Gsps mode and not in 2Gsps mode.
 

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Re: Conversion of 500MHz TDS744A to 1GHz TDS784A
« Reply #29 on: July 02, 2016, 12:38:23 am »
Continuation ...

Having modified the hardware I used the Tektronix Field Adjustment software to calibrate the scope. The software calls for the use of a SG504 levelled signal generator. I don't have one of these. I used an Agilent E4425B RF Generator and very high quality cable. I found I had to increase the generator output by 5% when the software called for frequencies higher than 500 MHz to compensate for losses in the cable.

After a couple of false starts I was able to calibrate the scope.

[images snipped]

It looks like a successful conversion  :D :D :D

Enjoy !!!

Jay_Diddy_B

Nice job!  :-+ You inspired me to try this on a TDS754A. However, I hit a roadblock on the HF_CAL. Like you, I don't have a Tek SG504, and instead tried using a R&S SMT 03. The SMT 03 only has output to +13dBm / 1.0V. This is not enough for the calibration to continue (I didn't find this out until almost 2 hours into the cal process.  |O Now all the calibration constants are Initialized.

Do you remember the max amplitude you needed to use on your E4425B during HF_CAL?
Looking at the specs on the E4425B, it too also has a max of 13dBm. Do you have Option UNB high output which gives +17dBm?

Looks like I'll need to score an amplifier - I was looking at HP 8447D amps but they are a bit pricey!
EDIT: not only that, but the output is only +7dBm - never mind...

Anyone have any recommendations for a low cost amp with a minimal frequency range of 6MHz to 1.05GHz?

Thanks!

Jay
« Last Edit: July 02, 2016, 12:48:17 am by Jwalling »
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Offline nctnico

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Re: Conversion of 500MHz TDS744A to 1GHz TDS784A
« Reply #30 on: July 02, 2016, 01:51:58 am »
How about getting a simple mmic based amplifier?
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Offline Jay_Diddy_B

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Re: Conversion of 500MHz TDS744A to 1GHz TDS784A
« Reply #31 on: July 02, 2016, 02:26:37 am »
Hi,

As well as needing high amplitude, the signal needs to be levelled. That is the amplitude needs to  be constant over the frequency range.

You may trouble if you use a MMIC amplifier.

Regards,

Jay_Diddy_B
 

Offline nctnico

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Re: Conversion of 500MHz TDS744A to 1GHz TDS784A
« Reply #32 on: July 02, 2016, 02:33:51 am »
Hi,

As well as needing high amplitude, the signal needs to be levelled. That is the amplitude needs to  be constant over the frequency range.

You may trouble if you use a MMIC amplifier.
If you use an RF generator you can adjust the amplitude so the output of the MMIC is correct.
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Online edavid

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Re: Conversion of 500MHz TDS744A to 1GHz TDS784A
« Reply #33 on: July 02, 2016, 02:38:50 am »
Looks like I'll need to score an amplifier - I was looking at HP 8447D amps but they are a bit pricey!
EDIT: not only that, but the output is only +7dBm - never mind...

The 8447E is the power amp version, with +12.5dBm output.

 
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Online Jwalling

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Re: Conversion of 500MHz TDS744A to 1GHz TDS784A
« Reply #34 on: July 02, 2016, 02:41:34 am »
Looks like I'll need to score an amplifier - I was looking at HP 8447D amps but they are a bit pricey!
EDIT: not only that, but the output is only +7dBm - never mind...

The 8447E is the power amp version, with +12.5dBm output.

And that's not enough either.  :(

Jay
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Offline timb

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Re: Conversion of 500MHz TDS744A to 1GHz TDS784A
« Reply #35 on: August 11, 2016, 10:13:43 am »
So, last night I took the plunge and did the conversion on my newly acquired TDS 754C.

Initially, all resistors *except* R1064 were populated:



To convert it to a TDS 784C, I removed R1061-63 and populated R1064:



Then I carefully removed the four capacitors, cleaned the area with foam swabs and isopropyl alcohol and reassembled the scope. She booted right up as a TDS 784C!

I hooked my TG 501 Time Mark Generator up, set it to 1ns markers and turned the scope down to the 200ps setting:



So far so good! Let's see how the signal looks in normal mode:



Now, some of the weirdness may be on the TG 501's end, I'm just not certain. (It came to me in pieces and I was never able to calibrate the 1ns output, because until now I didn't have a scope capable of it).

Anyway, I'm pretty happy with the conversion! I haven't calibrated it yet (because I don't have a signal generator that will go that high), but for now it's alright. At least I can get a good idea of higher frequency stuff now, plus there seems to be no change on the 2GS/s or lower ranges, so I can still rely on them and know they're accurate. (I assume this is because the scope already had the cal data up to 500MHz.)

Now to find a proper signal generator to do the calibration! Maybe I'll get lucky and find a SG 504 on the cheap; people want ridiculous amounts for them on eBay, even without the leveling head (which the unit is useless without).
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Re: Conversion of 500MHz TDS744A to 1GHz TDS784A
« Reply #36 on: August 11, 2016, 10:56:58 am »
Way to go Tim - I was always too scared to try the conversion since I had no real backup option. Now your 750Mhz active probes are not enough and you will be wanting faster ones. The cycle never ends.  :-DD

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Offline timb

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Conversion of 500MHz TDS744A to 1GHz TDS784A
« Reply #37 on: August 11, 2016, 11:13:43 am »
Way to go Tim - I was always too scared to try the conversion since I had no real backup option. Now your 750Mhz active probes are not enough and you will be wanting faster ones. The cycle never ends.  :-DD

Thanks! I actually got use my hot tweezers to remove the resistors. I bought them like two years ago and they've just sat in my soldering box... Worked perfectly though, no pulled traces or marks on the board!

I hadn't even thought of my probes... Better update my eBay searches!

Speaking of which, I just scored an SG 504 for $100 (the guy had it listed for $800)! No leveling head, but I did find schematics and a PCB layout for a DIY replacement. (There's even a guy on eBay who builds and calibrates them to 0.1%, which is ten times better than the original Tek head! He wants $120 though, so I'll have a crack at building one myself first.)
« Last Edit: August 11, 2016, 11:16:15 am by timb »
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Re: Conversion of 500MHz TDS744A to 1GHz TDS784A
« Reply #38 on: August 11, 2016, 11:25:59 am »
I have been hoping to get my hands on one of these fast pulse generators. Designed by esteemed forum member based on the Jim Williams design but with some clever updates.

I would love to get a kit, or gerbers, or a built unit, whatever. Obviously you need a proper signal generator first to calibrate, but it could be used to see how the scope responds to a fast edge. Since it only samples at 2Gs/s - you are right at the Nyquist at 1Ghz where the front end starts to roll off.
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Offline Jay_Diddy_B

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Re: Conversion of 500MHz TDS744A to 1GHz TDS784A
« Reply #39 on: August 11, 2016, 12:09:39 pm »
Hi,

Part of the calibration process is to adjust the timing between the samplers. The samplers are interleaved at the high sampling rates. When you do this the waveforms become a lot smoother. This a picture of mine after the calibration:



The scope use Equivalent Time sampling, indicated by the ET on the screen. Different parts of the waveform are acquired on different acquisitions. This fine for repetitive waveforms, but no use for single shot events.

There are a couple of Avalanche pulse generators on this forum. There is one designed by Free Electron.
This uses the 2N2369 transistor.

That thread can be found here:

http://www.eevblog.com/forum/blog/eevblog-306-jim-williams-pulse-generator/


I designed one that uses a BFR505 transistor which is significantly faster.

The thread starts here: http://www.eevblog.com/forum/projects/transmission-line-avalanche-pulse-generator/



I got to this level of performance:



This is measured with a 20 GHz scope.


This is what the risetime of my 744A looks like after conversion and calibration:






You need a waveform with a flat top to measure the risetime. If you don't you can get very optimistic results.

Good luck !!

Jay_Diddy_B


« Last Edit: August 11, 2016, 12:12:49 pm by Jay_Diddy_B »
 

Offline Jay_Diddy_B

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Re: Conversion of 500MHz TDS744A to 1GHz TDS784A
« Reply #40 on: August 11, 2016, 12:26:52 pm »
Hi,

I managed to get the Tektronix field adjustment software to run in an automated manner.

I got some useful tips from this YouTube video:



This guy has some other similar videos, but he stops short of giving all the answers.

The Tektronix software is not all that friendly.

I found that it worked for me with the following equipment:

Hp3478A DMM
Analogic (Data precision) 8200 DC voltage standard
Fluke 6061A

You still have to move the cables around *a lot*

The software checks the high frequency cal for each channel in 20 MHz steps from 500MHz to 1 GHz if I remember correctly.

Some of the adventure is documented in this thread:

http://www.eevblog.com/forum/testgear/tektronix-tds700a-field-adjust-software-help-needed/msg563939/#msg563939


Regards,

Jay_Diddy_B
 

Offline cncjerry

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Re: Conversion of 500MHz TDS744A to 1GHz TDS784A
« Reply #41 on: August 11, 2016, 01:31:33 pm »
I have been hoping to get my hands on one of these fast pulse generators. Designed by esteemed forum member based on the Jim Williams design but with some clever updates.

I would love to get a kit, or gerbers, or a built unit, whatever. Obviously you need a proper signal generator first to calibrate, but it could be used to see how the scope responds to a fast edge. Since it only samples at 2Gs/s - you are right at the Nyquist at 1Ghz where the front end starts to roll off.

After the upgrade the sample time is doubled to 4G.  There was also a way to enable the rest of the memory using software and a switch in the side. 
 

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Re: Conversion of 500MHz TDS744A to 1GHz TDS784A
« Reply #42 on: August 13, 2016, 10:09:07 am »
I had no idea the hardware could do that. Awesome.

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Offline cncjerry

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Re: Conversion of 500MHz TDS744A to 1GHz TDS784A
« Reply #43 on: August 13, 2016, 10:59:27 am »
The 784 scope is just a beast.  I have a 3054B as well and though it is loaded with features, when I need to stare at a signal, I use my upgraded 784.  It has a very, very crisp display no matter what the detractors say about the shutter.  The colors are rich, much more so than an LED display. I often wonder why these displays weren't advanced. It's clear to me that the LED display is inferior and is used to cut cost like a front wheel drive car; sold as better but really just a way to cut manufacturing costs.

One thing I have to dig into on mine, is it seems like my scope has a lot of noise on the probe compensation test points.  It could be just the local FM stations leaking through the probe cables.  Do you guys see that as well?  put it in envelope mode and probe the test points.

Thanks
 

Offline timb

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Re: Conversion of 500MHz TDS744A to 1GHz TDS784A
« Reply #44 on: August 13, 2016, 11:14:03 am »
The 784 scope is just a beast.  I have a 3054B as well and though it is loaded with features, when I need to stare at a signal, I use my upgraded 784.  It has a very, very crisp display no matter what the detractors say about the shutter.  The colors are rich, much more so than an LED display. I often wonder why these displays weren't advanced. It's clear to me that the LED display is inferior and is used to cut cost like a front wheel drive car; sold as better but really just a way to cut manufacturing costs.

One thing I have to dig into on mine, is it seems like my scope has a lot of noise on the probe compensation test points.  It could be just the local FM stations leaking through the probe cables.  Do you guys see that as well?  put it in envelope mode and probe the test points.

Thanks

The probe calibrator on the TDS 5/7xx series is pretty crappy when compared to some of Tektronix's previous work (like the calibrator on the 2465 series, which automatically changes frequency from 100Hz to 5MHz, depending on what sweep rate you've got set; the output is semi-regulated and has very fast rise and fall times).

On these TDS scopes, the calibration signal is provided by the little MCU on the front panel (it monitors the pots and buttons and talks to the CPU over a serial interface). Basically, it's just programmed to waggle a GPIO at 1kHz, which is then amplified by a transistor.

It's powered by the 5V digital supply, if I remember right, so I'm sure that couples in significant noise. Hitting buttons or twirling knobs will also cause the signal to occasionally drop pulses.

Honestly, an RC oscillator or 555 timer would have been better than using the MCU, but for compensating probes I guess it does the job... (I always use the Fast Rise output of my PG 506 or my 2465B's output for probe compensation anyway, so it doesn't bother me much.)
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Offline Wuerstchenhund

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Re: Conversion of 500MHz TDS744A to 1GHz TDS784A
« Reply #45 on: August 13, 2016, 09:03:40 pm »
The 784 scope is just a beast.  I have a 3054B as well and though it is loaded with features, when I need to stare at a signal, I use my upgraded 784.  It has a very, very crisp display no matter what the detractors say about the shutter.  The colors are rich, much more so than an LED display. I often wonder why these displays weren't advanced. It's clear to me that the LED display is inferior and is used to cut cost like a front wheel drive car; sold as better but really just a way to cut manufacturing costs.

I'm sorry but that is nonsense.

NuColor had a better contrast ratio (thanks to the b/w CRT and the contrast enhancing filter in front of it) and cleaner reproduction of saturated colors than the average color CRT with mask back then, and that was supported by a UI color scheme that mostly relies on highly saturated colors and the use of high contasts (you'll also see the same saturation if you connect an external display, and the TFT retrofit kits that are available for these scopes give pretty much the same "rich" colors as the old NuColor display).

Back in the early '90s NuColor helped Tek to keep costs low (a mono CRT plus the simple LCD shutter was cheaper than a color CRT plus associated circuitry) while avoiding the convergence/sharpness issues which were common to color CRTs. But NuColor became pretty much obsolete when CCFL backlighted TFT panels became mainstream and costs of these panels came down enough thanks to mass production.

The idea that NuColor is superior to a modern TFT panel with LED backlight is silly, really, especially when considering how bad NuColor was at reproducing non-saturated colors or nuances between colors, something modern TFT panels have little problems with. NuColor is gone because it was a technological dead relying on obsolete technology (CRT).
« Last Edit: August 13, 2016, 09:08:39 pm by Wuerstchenhund »
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Offline timb

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Re: Conversion of 500MHz TDS744A to 1GHz TDS784A
« Reply #46 on: August 13, 2016, 10:04:10 pm »
The 784 scope is just a beast.  I have a 3054B as well and though it is loaded with features, when I need to stare at a signal, I use my upgraded 784.  It has a very, very crisp display no matter what the detractors say about the shutter.  The colors are rich, much more so than an LED display. I often wonder why these displays weren't advanced. It's clear to me that the LED display is inferior and is used to cut cost like a front wheel drive car; sold as better but really just a way to cut manufacturing costs.

I'm sorry but that is nonsense.

NuColor had a better contrast ratio (thanks to the b/w CRT and the contrast enhancing filter in front of it) and cleaner reproduction of saturated colors than the average color CRT with mask back then, and that was supported by a UI color scheme that mostly relies on highly saturated colors and the use of high contasts (you'll also see the same saturation if you connect an external display, and the TFT retrofit kits that are available for these scopes give pretty much the same "rich" colors as the old NuColor display).

Back in the early '90s NuColor helped Tek to keep costs low (a mono CRT plus the simple LCD shutter was cheaper than a color CRT plus associated circuitry) while avoiding the convergence/sharpness issues which were common to color CRTs. But NuColor became pretty much obsolete when CCFL backlighted TFT panels became mainstream and costs of these panels came down enough thanks to mass production.

The idea that NuColor is superior to a modern TFT panel with LED backlight is silly, really, especially when considering how bad NuColor was at reproducing non-saturated colors or nuances between colors, something modern TFT panels have little problems with. NuColor is gone because it was a technological dead relying on obsolete technology (CRT).

Well, LCDs didn't become fast enough to replace CRT's (for anything with motion in them) until the early 2000's at the earliest. (And even then, hardcore gamers still used CRTs right up until the mid-2000's because LCDs still had slightly perceptible ghosting.)

Then there's the CCFL issue that wasn't really solved until the late-2000's thanks to white LEDs. There's also the issue of full color depth, which you can't get without an expensive IPS panel.

I also don't think NuColor helped keep costs low... In fact, I'd be surprised if a color CRT wouldn't have been a lot cheaper. Linearity and other issues had been pretty much solved by then, due to rapid advances spurred by the computer industry.

Nobody said a NuColor display is better than a modern LCD. The implication is that, if the technology had kept being developed, it could potentially be better. Perhaps it could have been combined with a mono plasma display or even those ultra low profile CRTs that were developed (but never went into mass production) in the early to mid 2000's.

I've got to say, I absolutely love the display on my 754C as well. It's light years better than any LCD could have possibly been of that vintage. In fact, I even like it better than the LCD on my MSO2024B, which *is* modern! It's fast, absolutely oozes contrast, displays a full gamut of colors... It's gorgeous.

(Just a small correction: NuColor was originally designed for electrostatic deflection CRTs [originally it only provided two colors, plus white] for one of Tek's 5000 series scopes in the early 80's.)
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Offline Wuerstchenhund

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Re: Conversion of 500MHz TDS744A to 1GHz TDS784A
« Reply #47 on: August 13, 2016, 11:20:30 pm »
Well, LCDs didn't become fast enough to replace CRT's (for anything with motion in them) until the early 2000's at the earliest. (And even then, hardcore gamers still used CRTs right up until the mid-2000's because LCDs still had slightly perceptible ghosting.)

TFTs exited well before the 2000's (HP put one in their Infiniium 54800 scopes back in 1997, as did other scope manufacturers around the same time), and were more than fast enough for stuff like scopes or even motion scenes.

Gamers often used CRTs even after 2000 because they could be operated at higher refresh rates than 60Hz (a limit of LCDs back then), which was necessary to maintain high frame rates as with VSYNC enabled the frame rate is limited by the screen's refresh rate (and without VSYNC there's lots of ugly tearing). Also, many desktop LCD displays came with slow panels to keep prices down.

Quote
Then there's the CCFL issue that wasn't really solved until the late-2000's thanks to white LEDs.

What 'CCFL issue'?

Quote
There's also the issue of full color depth, which you can't get without an expensive IPS panel.

True, but even a cheap TN exceeds the color reproduction capabilities of the these shutter displays.

Quote
I also don't think NuColor helped keep costs low...

Tek at least thought so, as it was in one of their press releases back then.

Quote
In fact, I'd be surprised if a color CRT wouldn't have been a lot cheaper. Linearity and other issues had been pretty much solved by then, due to rapid advances spurred by the computer industry.

Linearity was always a problem with color CRTs, right 'til the end. Replacement of sea of pots with microprocessor controls and self adjustment capabilities did provide some improvements but the problem never went away. As to price, it's not just the price of the tube itself but also the circuitry. A color CRT display is notably more complex than a monochrome display, and the simple shutter required only very little additional circuitry plus some software changes.

Quote
Nobody said a NuColor display is better than a modern LCD.

I believe this is exactly what cncjerry implied.

Quote
The implication is that, if the technology had kept being developed, it could potentially be better. Perhaps it could have been combined with a mono plasma display or even those ultra low profile CRTs that were developed (but never went into mass production) in the early to mid 2000's.

It is highly unlikely that a technology that relies on a fragile vacuum-ized glas containment and very high voltages could ever have kept up with LCDs which are inherently free of linearity/convergence problems, more robust, have a longer service life, use less power and are cheaper to manufacture. And, like it or not, Plasma is dead for pretty much the same reason.

Quote
I've got to say, I absolutely love the display on my 754C as well. It's light years better than any LCD could have possibly been of that vintage. In fact, I even like it better than the LCD on my MSO2024B, which *is* modern! It's fast, absolutely oozes contrast, displays a full gamut of colors... It's gorgeous.

Not saying the display on the TDS700C isn't good, and I can see why you prefer it to that cheap-ass TN in the MSO2024B (which is pretty poor), although the MOS2k's UI certainly plays its part as well. But in reality there is no "full gamut of colors" (and even if the display was capable of it, which it isn't, you couldn't possibly say because the scope hardware can't do more than 256 colors, and the UI uses a lot less than that), and while it fulfilled its purpose of providing a crisp and clear display for a digital scope, it's definitely no competition for a decent LCD.
« Last Edit: August 13, 2016, 11:24:13 pm by Wuerstchenhund »
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Offline timb

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Re: Conversion of 500MHz TDS744A to 1GHz TDS784A
« Reply #48 on: August 13, 2016, 11:57:07 pm »
Well, LCDs didn't become fast enough to replace CRT's (for anything with motion in them) until the early 2000's at the earliest. (And even then, hardcore gamers still used CRTs right up until the mid-2000's because LCDs still had slightly perceptible ghosting.)

TFTs exited well before the 2000's (HP put one in their Infiniium 54800 scopes back in 1997, as did other scope manufacturers around the same time), and were more than fast enough for stuff like scopes or even motion scenes.

Gamers often used CRTs even after 2000 because they could be operated at higher refresh rates than 60Hz (a limit of LCDs back then), which was necessary to maintain high frame rates as with VSYNC enabled the frame rate is limited by the screen's refresh rate (and without VSYNC there's lots of ugly tearing). Also, many desktop LCD displays came with slow panels to keep prices down.

Quote
Then there's the CCFL issue that wasn't really solved until the late-2000's thanks to white LEDs./
Quote

What 'CCFL issue'?

Quote
There's also the issue of full color depth, which you can't get without an expensive IPS panel.

True, but even a cheap TN vastly exceeds the color reproduction capabilities of NuColor.

Quote
I also don't think NuColor helped keep costs low...

Tek at least thought so, as it was in one of their press releases back then.

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In fact, I'd be surprised if a color CRT wouldn't have been a lot cheaper. Linearity and other issues had been pretty much solved by then, due to rapid advances spurred by the computer industry.

Linearity was always a problem with color CRTs, right 'til the end. Replacement of sea of pots with microprocessor controls and self adjustment capabilities did provide some improvements but the problem never went away. As to price, it's not just the price of the tube itself but also the circuitry. A color CRT display is notably more complex than a monochrome display, and the simple shutter required only very little additional circuitry plus some software changes.

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Nobody said a NuColor display is better than a modern LCD.

I believe this is exactly what cncjerry implied.

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The implication is that, if the technology had kept being developed, it could potentially be better. Perhaps it could have been combined with a mono plasma display or even those ultra low profile CRTs that were developed (but never went into mass production) in the early to mid 2000's.

It is highly unlikely that a technology that relies on a vacuum-ized glas containment and very high voltages could ever have kept up with LCDs which are inherently free of linearity/convergence problems, more robust, have a longer service life, use less power and are cheaper to manufacture. And, like it or not, Plasma is dead for pretty much the same reason.

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I've got to say, I absolutely love the display on my 754C as well. It's light years better than any LCD could have possibly been of that vintage. In fact, I even like it better than the LCD on my MSO2024B, which *is* modern! It's fast, absolutely oozes contrast, displays a full gamut of colors... It's gorgeous.

Not saying the display on the TDS700C isn't good, and I can see why you prefer it to that cheap-ass TN in the MSO2024B (which is pretty poor).  But in reality there is no "full gamut of colors" (and even if the display was capable of it, which it isn't, you couldn't possibly say because the scope hardware can't do more than 256 colors, and the UI uses a lot less than that), and while it fulfilled its purpose of providing a crisp and clear display for a digital scope, it's definitely no competition for a decent LCD.

I know LCDs existed before 2000.... My point was that they were extraordinarily laggy. Yes, even the "Active Matrix" TFT ones.

Refresh rate had nothing to do with why gamers used CRTs. Nobody kept VSYNC on either because, like you said, it limited frame rate. The reason CRTs were used by hardcore gamers has absolutely everything to do with the fact there was no ghosting in the image. No lag. In 2000 even the best LCDs you could get still had lag in the >100ms. I know, because I had a state of the art $1500 Sony LCD, but I still used a Trinitron CRT for gaming. (I was in the #2 ranked East Coast Quake III clan.)

The problem with CCFLs is they have a very finite life, while for the most part CRTs don't. (Though, to be fair, I hear some of the NuColor shutters also have a finite life due to bonding issues.)

Just because LCDs are a cheaper technology doesn't make them better. I personally think plasma TVs have much better pictures compared to LCD sets. Unfortunately it's an expensive technology that has heat and burnin issues, that's why it's basically dead.

The NuColor display on the TDS series is capable of reproducing all 256 colors of the VGA palette pretty clearly, so I don't know why you're saying it's not capable of it?

I'd like to see that press release from Tek talking about NuColor being cheaper than a color CRT. For some reason I just can't imagine it being cheaper. Hell, HP had been using color CRTs since the 80's on their logic analyzers. LeCroy had some of those big ass 1GHz scopes with color CRTs, mid to late 90's vintage, right? (The ones with the thermal printers; they replaced the models with Amber CRTs.)

Keep in mind that NuColor wasn't originally designed for use on a raster scan display. It was designed to produce a color electrostatic CRT for analog oscilloscopes. (It also commanded a $1500 premium compared to the B&W only model when it was originally released in 1984!)

For use on a scope, faced with the choice between:

A) NuColor Display from 1995
B) Color CRT from 1995
C) Color LCD from 1995

I'll take A every single time, with B coming in second. In fact I'd take a monochrome CRT before I took option C!

I guess my point is, up until the early 2000's, LCDs were not a realistic option for oscilloscopes (yes, a few had them, but they were either absolute budget models with blurry monochrome LCDs or very high end models with clear yet expensive color displays).
Any sufficiently advanced technology is indistinguishable from magic; e.g., Cheez Whiz, Hot Dogs and RF.
 

Offline andy2000

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  • Posts: 140
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Re: Conversion of 500MHz TDS744A to 1GHz TDS784A
« Reply #49 on: August 14, 2016, 01:12:57 am »
JVC made a small professional video monitor that used the same technology.  It has no trouble reproducing the full color depth of a TV image.  The only issue it has is the slight color fringing on fast motion. 

http://pro.jvc.com/pro/pr/nab/tml450tu.htm
 


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