How to meter digital/analog signal.

[arshull]

Anyone familiar with how to use a DMM and meter an analog or digital signal? How do you tell the difference between the two types of signals (when metering)?

Basically, I'm working on a project and trying to determine if the signal going from the HU to factory amp is analog or digital. Vehicle is too new and there is no literature on it.

Any help is greatly appreciated!

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[trumpet 5,000+ posts]

Digital is 1s and 0s and a DMM will not read that. Analog means it's AC voltage, and the meter will move up and down as music is playing.

 

[arshull]

Digital is 1s and 0s and a DMM will not read that. Analog means it's AC voltage, and the meter will move up and down as music is playing.

I understand that but would think that a digital signal would also carry some sort of minimal amperage/voltage or unique resistance.

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[fasfocus00 5,000+ posts]

I understand that but would think that a digital signal would also carry some sort of minimal amperage/voltage or unique resistance.
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it would but it can be synchronous or asynchronous. the only way to really tell would be to put it on an oscilloscope b/c a DMM doesn't measure time. how about you tell us what vehicle it is and we might know. you are also dealing with possibly testing the wrong wire, ask around to some techs who send voltage through twisted wires going into a door thinking it's speaker wires but find out the hard way it's actually part of an airbag deploy module.

 

[arshull]

it would but it can be synchronous or asynchronous. the only way to really tell would be to put it on an oscilloscope b/c a DMM doesn't measure time. how about you tell us what vehicle it is and we might know. you are also dealing with possibly testing the wrong wire, ask around to some techs who send voltage through twisted wires going into a door thinking it's speaker wires but find out the hard way it's actually part of an airbag deploy module.

Its in a 2015 Mustang. I've posted on here before asking about this vehicle but think its too new for anyone to have much experience with it. I do have the wiring diagram from ford and tapping into the harnesses at the factory amp. Already confirmed the diagram is accurate just trying to determine the input type.

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[fasfocus00 5,000+ posts]

amp input is going to be analog

 

[arshull]

amp input is going to be analog

OK, so I can just solder some rca cables to the amp inputs and run to the aftermarket amps correct? I already know they are low-level signals. Can't use a output convertor on the amp outputs BC a previous installer lost the connector that comes out of the amp.... Hence why I'm trying to problem solve the amp inputs.

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[fasfocus00 5,000+ posts]

OK, so I can just solder some rca cables to the amp inputs and run to the aftermarket amps correct? I already know they are low-level signals. Can't use a output convertor on the amp outputs BC a previous installer lost the connector that comes out of the amp.... Hence why I'm trying to problem solve the amp inputs.
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so you have no speaker connections? how does an installer lose a connector?

 

[arshull]

so you have no speaker connections? how does an installer lose a connector?

Correct. He lost the entire output connector that comes out of the amp. That was just one of many amazing things this guy managed to accomplish. He cut the output wires about an inch from the connector and then lost the connector. Amazing!

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[fasfocus00 5,000+ posts]

first why would one cut off a connector? second if you were cutting it off why would you only give yourself 1" of wire.

 

[Boominburban 10+ year member]

you are confusing the term "installer" with the term "back yard hack" .....please refrain from this in future posts .... As it gives real installers a bad name ...

 

[arshull]

you are confusing the term "installer" with the term "back yard hack" .....please refrain from this in future posts .... As it gives real installers a bad name ...

You are absolutely right !! Will re-word in the future.

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[arshull]

first why would one cut off a connector? second if you were cutting it off why would you only give yourself 1" of wire.

Very good question. A lot of things he did make no sense! Ruined a very nice car. Luckilly, I have it put back together and will sound great when finalized.

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