UT81B

[R_G_B_]

I have a ut81B scope meter and was wondering if it would be possible to mod it slightly just to improve the bandwidth slightly so it can at least show a 1Mhz sqaure wave. The divice has what seems like a master slave configuration e.g

The LPC 2138 drives the cyclone 2 FPGA which drives the display and is runs off a 12MHz crystal. The LPC arm chip is running of its on own internal clock.

The ADC is a 98283. There are 3 version of this ADC 50mhz 80mhz and 100mhz with identical connections.   

Question is if I double the clock frequency and the ADC to 100Mhz does this make the ut81B the same spec as the ut81C? obviously it has a software change to allow the time base to go to 50ns. But nothing more than that.   

The low noise analogue amplifier at the front end is onlt 50Mhz analogue bandiwth
which may be causing the problems attentuation at high frequency causing the pulse shape to to have distortion.

Also the circuits are very noisy.

Is there any way to reverse engineer the FPGA and LPC software?

Something to do a hack project.

R_G_B_

[Bored@Work]

Why do you think modifying a 8 MHz BW, 40MS/s "oscilloscope" is needed to view a 1 MHz square wave?

[dr_p]

The UT81B has a bandwidth of 8MHz so it's perfectly capable of displaying a 1MHz square wave(the 3rd harmonic is 7Mhz)  . In here there are photos of the scope doing these measurements.

 
So I don't understand what you want to hack it for. 

 

[R_G_B_]

The Ut81b shows a lot of distortion on my scope at 1mhz when set to frequency measurement. Would be interesting to see where  its limitations are by changing a few components. According to The ADC data sheet it has an analogue bandwidth of up to 400Mhz.

[Wytnucls]

There is a UT81C version, with higher specs.
http://www.ebay.com/itm/UNI-T-Handheld-Digital-Multimeter-3999Counts-16MHz-Multimeter-UT81C-/380647788963?pt=LH_DefaultDomain_0&hash=item58a06051a3

[R_G_B_]

Yes the specs for the scope are 16MHz analogue and width double that of the ut81b.
So did they just double the crystal clock from 12MHz to 24MHz and the ADC to 100MHz
Just altering the software to  50ns time base? Not sure about the amplifier though?

[R_G_B_]

Be interesting if someone had a UT81C so that we could see the difference in components used between the two to give the different bandwidth.