Hitachi Oscilloscope V-212 testing question

Thread Starter

Automan350

Joined Jun 15, 2015
45
The Hitache V-212 oscilloscope has a bandwidth of 20MHz and will be ideal for the TS application. A modern digital oscilloscope with FFT capability is a very expensive tool. I made my own audio spectrum analyser using a ATMega328 microcontroller with a 1.7" OLED color display.
I noticed the device operates between 1.8-5.5 volts. That is fine by me. I can keep the voltage in that range.
 

KeithWalker

Joined Jul 10, 2017
2,607
I noticed the device operates between 1.8-5.5 volts. That is fine by me. I can keep the voltage in that range.
The one I designed has an adjustable input level control with an overload indicator. It only goes up to 16KHz and does not have terribly good resolution but it has 3 frequency ranges - 0 to 4KHz, 0 to 8KHz and 0 to 16KHZ. I also has a memory option so it will store and display a frequency swept signal. That is good for plotting frequency displays of filters and cross-over networks.
I do still have the circuit, PC layout and program. It will take a few days to put it all together in a package but I will PM it to you.

SpecA2 001.jpg
 

KeithWalker

Joined Jul 10, 2017
2,607
How cool is that! Nice job man!

Thank you for your time.
Just a thought: Do you have any experience using Arduino modules and software? You are going to need it to program a ATMega328. My notes on the SA are fairly sparse so I am putting together a construction article. It will take a little time.
 

Thread Starter

Automan350

Joined Jun 15, 2015
45
Just a thought: Do you have any experience using Arduino modules and software? You are going to need it to program a ATMega328. My notes on the SA are fairly sparse so I am putting together a construction article. It will take a little time.
I do not. I'm in no rush, so take your time.

Thanks!
 

Thread Starter

Automan350

Joined Jun 15, 2015
45
The scope arrived yesterday. I was able to calibrate the probe. However when I set the scope to measure and connect it to the speaker outputs of my car stereo on the bench the scope goes crazy. Maybe it is due to the speaker being connected. Idk. I am not sure what I am doing wrong. Any assistance is appreciated.
 

Attachments

Thread Starter

Automan350

Joined Jun 15, 2015
45
This is a 50hz signal from my radio

We do this because you want to find the point (volume) the radio starts to clipp. If we keep it under that we can install speakers that are rated for or above that voltage(watts) and not have any failures.
 

Attachments

MrChips

Joined Oct 2, 2009
27,669
This is a 50hz signal from my radio

We do this because you want to find the point (volume) the radio starts to clipp. If we keep it under that we can install speakers that are rated for or above that voltage(watts) and not have any failures.
If the output is clipping it is doing so in the amplifier stage. Changing the speaker wattage is not going to make the clipping go away.
 

Thread Starter

Automan350

Joined Jun 15, 2015
45
I agree.
What I am trying to say is we have options. I'm not sure how to explain this. I do agree that the speaker rms has nothing to do with the amplifier clipping point.

I do wish to figure this out so I can find the clipping points in my systems.

I am sure I have something set incorrectly.
 

KeithWalker

Joined Jul 10, 2017
2,607
Can you be a little more specific when you state that "the scope goes crazy"? How is the scope connected to the speaker? Where is the ground clip connected? The receiver may have a bridged output. In that case, neither side of the speaker is connected to the car ground. If you ground one side of it you may damage the output circuit.
 

Thread Starter

Automan350

Joined Jun 15, 2015
45
Can you be a little more specific when you state that "the scope goes crazy"? How is the scope connected to the speaker? Where is the ground clip connected? The receiver may have a bridged output. In that case, neither side of the speaker is connected to the car ground. If you ground one side of it you may damage the output circuit.
I read this and thought maybe that was it.

I had the ground connected to the negative output. I moved the ground clip to the radio metal frame and i think that fixed my issue as I now can read a sine wave.

The line on the scope screen flickers when reading, so I may still have something set incorrectly. However I am now able to read the sine wave and see at volume level 27 Is when the clipping starts.
 

Attachments

tautech

Joined Oct 8, 2019
306
The sine wave is solid on my scope. The picture can't catch the flickering
Welcome to the limitations of a CRO !
Fine for a repetitive waveforms but little else, glitches well good luck seeing them with ordinary phosphors let alone being able to trigger on them !

I made a statement a few posts back that you'd be far better off with a DSO and their significantly greater capabilities and I'll remind you again the days of CRO's in modern electronics are past. Sell it as a working scope and get yourself a new DSO but not too old design, say a SDS1202X-E would be a far better choice than a decades old Hitachi.
 

Thread Starter

Automan350

Joined Jun 15, 2015
45
Welcome to the limitations of a CRO !
Fine for a repetitive waveforms but little else, glitches well good luck seeing them with ordinary phosphors let alone being able to trigger on them !

I made a statement a few posts back that you'd be far better off with a DSO and their significantly greater capabilities and I'll remind you again the days of CRO's in modern electronics are past. Sell it as a working scope and get yourself a new DSO but not too old design, say a SDS1202X-E would be a far better choice than a decades old Hitachi.
When I look at the sine wave it is complete and centered.
The camera shows part of the sine wave.
 
Top