low cost DSO able to plot the Frequency Response?

[DiTBho]

With a budget of 200 euro, is there anything able to plot the frequency response in the bandwidth of 50Hz..5Mhz?

[DiTBho]

In theory, you can plot the frequency response by

• using a DDS to generate a sin(wt) wave of 1V of amplitude and parametric frequency, say from 50 Hz to 5Mhz
• injecting the generated A*sin_in(wt+phi_A) wave into the input of the circuit you want to analysis
• measuring the output B*sin_out(wt+phi_B)
• for each frequency, the ratio B/A is the gain in the frequency response plot
• I don't know to to measure the phase difference between (phi_A - phi_B)

Code: [Select]

                                   |             |
DDS(w) ---- A*Sin(w*t+phi_A) ----->|   circuit   |------- B*sin(w*t+phi_B)
                                   |_____________|



I wish I had the money to buy something like this: DSO 

[tautech]

Exploring the FRA limits of the $499 SDS1104X-E:
https://www.eevblog.com/forum/testgear/siglent-sds1x04x-e-bodeplot-ii-(sfra)-features-and-testing-(coming)/

[bestel]

Do you really need to see the phase?

If not, you can do a sweep with a function generator, and look at the trace on a oscilloscope (assuming you have already all this stuff).

Or, you can do the old way, by making all manually... depending how many points you want, and how many time you need to do it, it can be interesting.

[khs]

Here a cheap oszilloscope (cheap means cheap so don't expect too much..).

https://www.conrad.de/de/p/voltcraft-dso-2020-usb-usb-oszilloskop-20-mhz-2-kanal-48-msa-s-1-mpts-8-bit-digital-speicher-dso-122465.html
about Eur 130.-

It can display XY format, so you can see the phase...
But if possible, try to get a Rigol/Siglent..

It should be possible to find low cost function generator too....

[DiTBho]

It can display XY format, so you can see the phase...

That's a nice trick! Do you know if even low cost RIGOL have this function?

[ledtester]

Consider an Agilent Digilent Discovery:

https://youtu.be/0b5axyjXDW0

Version 2 units (both new and used) are kindy pricey, but you might be able to find a used version 1 on ebay for less.

[DiTBho]

Consider an Agilent Discovery:

WOW, perfect, thanks

[xmo]

Siglent: "The four channel SDS1000X-E can control the USB AWG module or control an independent SIGLENT SDG instrument, scan a device's amplitude and phase frequency response, and
display the data as a Bode Plot."

Keysight: "Frequency response analysis (gain & phase Bode plots) is a critical measurement to characterize amplifiers, passive networks, and power supply feedback networks. Bode plots are also fundamental concepts that every electrical engineering student should learn.

The 1000 X-Series’ frequency response analyzer capability (standard in “G” models) is the perfect tool to help students understand the gain and phase performance of passive RLC circuits and amplifiers. This capability is achieved with a gain and phase measurement versus frequency (Bode plot).

Vector network analyzers (VNAs) and low-cost frequency response analyzers are typically used for these measurements, but now an easy-to-use and affordable gain and phase analysis is possible by utilizing the 1000 X-Series’ built-in WaveGen and Bode plot capability."

[Fungus]

Siglent: "The four channel SDS1000X-E can control the USB AWG module or control an independent SIGLENT SDG instrument, scan a device's amplitude and phase frequency response, and
display the data as a Bode Plot."

Keysight: "Frequency response analysis (gain & phase Bode plots) is a critical measurement to characterize amplifiers, passive networks, and power supply feedback networks. Bode plots are also fundamental concepts that every electrical engineering student should learn.

The 1000 X-Series’ frequency response analyzer capability (standard in “G” models) is the perfect tool to help students understand the gain and phase performance of passive RLC circuits and amplifiers. This capability is achieved with a gain and phase measurement versus frequency (Bode plot).

Vector network analyzers (VNAs) and low-cost frequency response analyzers are typically used for these measurements, but now an easy-to-use and affordable gain and phase analysis is possible by utilizing the 1000 X-Series’ built-in WaveGen and Bode plot capability."

...and all for 200 Euros.