Recent Posts

1

Projects, Designs, and Technical Stuff / Re: (Yet Another) DIY Multislope ADC

« Last post by Kleinstein on Today at 08:18:47 pm »

There is no need for a perfect sync betwen the CPU and PIO part. Usually this is given as the PIO clock is from a divider. Only the possible fractional divider could cause trouble.

The sync problem would appear, when the CPU runs from the PLL and than external sync FF are used to directly synchronize to an external clock. This case is triky and if possible I would avoid it because of the complications with the phase, even if the PIO clock would be the same as the PLL input clock.

The more realistic case is an external clock (e.g. 20 MHz range) to directly run the CPUs. The PIO clock could even be a bit lower to get the delays without extra code.
Chances are one can skip an external sync step, though there is possibly a tiny bit of delay modulation from the µC internal state that could lead to a little INL.
If needed / wanted an external sync with 2 flip flops (the input path is not that critical and could be direct) is not that complicated if there is no PLL involved.

2

Test Equipment / Re: new killer scope in town - a true game changer from R&S - RTB2002 & RTB2004

« Last post by 2N3055 on Today at 08:13:59 pm »

I did not know that there was a kind of RT-ZP03 with 1x/10x switch, but is using this kind of probe not a
pain in the ass with a scope that can not autodetect the switch position?
There are very few reason why you should need a 1x probe with the limited bandwith on a 300Mhz scope with 12Bit.

> and all three waveform adjustments are now inside the small enclosure at the BNC connector.

I think that means your probes are the older type. The newer type has only two adjustment. The
third one is hidden behind the sticker.

> Nonetheless my last Rhode and Schwarz purchase.

I can understand. This company was always good in asking high price, but they became now bader in delivering a value for the money.
If I pay for a mercedes I like to drive one and not a beetle. (no 50R termination, no probe detection, fat probes)

Olaf

RTB2000 is not 12 bit.

3

Projects, Designs, and Technical Stuff / Re: Linear acceleration of stepper motor

« Last post by Andre Laloni on Today at 08:12:29 pm »

Nominal Animal, I am Andre, a new member in the Forum. I really appreciated your contributions to this topic and I would really like to pick your brain on this topic, as I am trying too develop some C++ code for Arduino to drive stepper motors in different acceleration/deceleration scenarios. They will all have a 5 phase cycles, being.: Stopped, Accelerate, Constant Speed, Decelerate, Stopped.
I am a mechanical engineer, having a my whole career working in investment banking. So coding and mechanical systems with stepper motors has ben my hobby! I am  new and self taught in coding, however, my largest challenge has been getting the correct equations into the programs. The math is what is making my life mode complicated as it has been difficult for me to isolate n (number of steps), λ(delay), ω((speed), t (time), ω'(acceleration), and p(position).
Is there a way I could get in touch with you.
Thank you very much.
Andre.

4

Projects, Designs, and Technical Stuff / Re: Accurate sine wave in terms of amplitude

« Last post by sw_guy on Today at 08:08:28 pm »

>Depending on your (apparently secret) requirements...

Or I simply don't know yet. Pretty much all the requirements (=the rest of the circuit) depend on what kind of signal I can generate. The frequency can be between 1-10kHz. Amplitude can be between 200mV and 5V. I don't know how much THD (or any other parameter) affects to the device. I need to finish the design, build the device and test. And then probably, re-design the circuit, build another device and test again. Maybe at this point I actually know all the key parameters, including if THD matters or not.

But I do know today that I am iterating options how to generate sine wave - as clarified in the initial message including an example circuit.

Quadrature oscillator might be "the fresh idea I was looking for". Just that none of the first examples I tried to simulate on LTspice didn't work. Like this one:


Probably a simulation related issue - I need to analyze it further...

sw guy

5

Projects, Designs, and Technical Stuff / Re: more modern version of tl494?

« Last post by 2strokeforever on Today at 08:04:43 pm »

Thanks, thats exactly what I needed to know.

Software control is way above my pay grade, and I would rather have more reliability.


UC3525A has:

• Pulse-by-Pulse Shutdown
• Latching PWM to Prevent Multiple Pulses

TL598 has "Internal Circuitry Prohibits Double Pulse at Either Output"

from what I can tell the TL598 can be used to limit pulse current

and an extra error amplifier


So far I am leaning towards the TL598 unless someone has good reasons to that the UC3525A might be better

6

Computers / Re: Format a 256GB pendrive with FAT32 using a windows 10 pc

« Last post by magic on Today at 07:59:29 pm »

I haven't seriously used Windows in 20 years, but I strongly suspect that any "slowness" is a matter of using right options, such as disabling "full formatting" (pointless overwriting of all space on the drive). Run it with /? first.

7

Test Equipment / Re: TDS 5XXX Series Oscilloscope External screen no trace

« Last post by gianrisa on Today at 07:59:23 pm »

Hey you should have two vga output, one it is the PPC outout and the other one is the Main board PC output. The Tekscope doesn't allow high resolution on the screen if you increase the resolution of the external screen you will not see any waveform output.

8

Test Equipment / Re: SDS800X HD Wanted Features

« Last post by ebastler on Today at 07:58:49 pm »

I wonder how many use these buttons.

Any advanced user with some active Math channels.

If you find yourself with some spare time, why don't you embark on reading the second sentence of eTobey's post? I am sure you will make it through...

The particular situation shwon in eTobey's screenshot seems awkward, but is probably due to the large fonts he has enabled. The only reason for the arrows to be shown is that the arrows take up room, so the CH1 box cannot be fully shown. In this case, there should be no arrows and all four channels boxes fully visible.

With the regular, smaller fonts, omitting the arrows would not make enough room available to show an additional full info box, I believe. So in general, I am fune with keeping the arrows.

9

Repair / Re: Help repairing Klipsch KDA amplifier power supply and identifying smd component

« Last post by r2digital on Today at 07:50:46 pm »

this is great, thank you! I do believe FDC655BN is the part

10

Test Equipment / Re: new killer scope in town - a true game changer from R&S - RTB2002 & RTB2004

« Last post by Darkover on Today at 07:45:00 pm »

I did not know that there was a kind of RT-ZP03 with 1x/10x switch, but is using this kind of probe not a
pain in the ass with a scope that can not autodetect the switch position?
There are very few reason why you should need a 1x probe with the limited bandwith on a 300Mhz scope with 12Bit.

> and all three waveform adjustments are now inside the small enclosure at the BNC connector.

I think that means your probes are the older type. The newer type has only two adjustment. The
third one is hidden behind the sticker.

> Nonetheless my last Rhode and Schwarz purchase.

I can understand. This company was always good in asking high price, but they became now bader in delivering a value for the money.
If I pay for a mercedes I like to drive one and not a beetle. (no 50R termination, no probe detection, fat probes)

Olaf