What will happen if an analog signal is passed through a DAC?

Hi:

What will happen if an analog signal is passed through a DAC [Digital- to-Analog Converter]?

Thanks

Reply to
GreenXenon
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Simulate it, it'll keep you occupied for hours.

And if you wait long enough, like several universe lifetimes, the DAC will spotaneously turn into an ADC. Maxim make them, you can get free samples.

Dave.

Reply to
David L. Jones

Assuming you are talking about a multiplying DAC, you will essentially have a digital volume control for the analog signal. The problem is that it will have a linear control range, not a logarithmic ("audio taper") range.

To do this, you use the analog signal as the reference voltage of the DAC. Note that not all DACs (and not even all multiplying DACs) can handle a bipolar reference. If yours can't, you just need to add the appropriate offset (and subtract afterwards), or AC-couple the signal and sum it with the normal reference so that the sum runs between 0 and the positive supply.

Best regards,

Bob Masta DAQARTA v4.51 Data AcQuisition And Real-Time Analysis

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Reply to
Bob Masta

I assume you mean the AC signal is applied to the DAC resistor chain and you are using the current output DAC as a digital resistor? I see no obvious problem with that...

Cheers

Reply to
Varactor

There's no problem with it, although unfortunately this sort of "multiplying DAC" approach tends to have significant frequency limitations -- it's pretty much impossible to find multiplying DACs that go beyond ~15MHz on the analog input.

Reply to
Joel Koltner

Lets say the analog signal is plotted on a graph two times, once before passing through the DAC and once after -- how will the two graphs differ?

A DAC is not meant to receive analog signal, so I suspect something weird and interesting might occur.

Reply to
GreenXenon

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In amplitude only.
Reply to
John Fields

Is that a trick question ?

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Reply to
Jamie

No, its a well known troll, formerly radium.

Reply to
Sjouke Burry

So the frequency and phase of both signals will be the same?

So the analog signal's peak-to-peak amplitude will decrease after being passed through the DAC?

Thanks

Reply to
GreenXenon

We used a DAC for the volume control on several models of our telemetry receivers. A lookup table allowed the CPU to move it in .1 dB steps.

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Reply to
Michael A. Terrell

No, and if you knew what you claim about electronics you would know that it works, and the limitations.

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Reply to
Michael A. Terrell

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 Google "R-2R ladder" for further enlightenment.
Reply to
John Fields

A.K.A. Multiplying DAC

Yes, multiplied by the DAC setting.

Or "Multiplying A/D Converter"

Reply to
krw

In article , snipped-for-privacy@att.zzzzzzzzz says...>

Sorry, "Multiplying D/A Converter"

Reply to
krw

You know, You are a complete asshole !...

One should question as to who really knows what they are doing.

You must of wasted a lot of employers money over the years, you wouldn't last long where I work.

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Reply to
Jamie

I would never work anywhere that they would hire a loser like you. I saved Microdyne, my last employer a lot of money by improving both manufacturing and test processes, as well as doing enough extra work in one night to make sure they received a half million dollar bonus for shipping some equipment ahead of schedule. My boss would tell me that I wouldn't take no for an answer, because I would take a problem directly to the president of the company if someone tried to ignore a problem. I took some test processes from half a day down to 18 minutes per board by improving the test fixtures, and having some parts changed from 1% to

0.1% tolerance and adding a precision voltage reference in the fixture.

I worked in engineering to move their RCB2000 & DR2000 designs from hand built prototypes to the production floor, including writing a lot of the test procedures, an building test fixtures. A lot of minor changes to the design had to be made to make it easier to build, and service, if needed. It also required a complete overhaul of our reflow process, because of the smaller SMD components we had to use to get everything one the VME style circuit boards. The Telemetry receiver was a dual DSP based system with a 70 MHz 40 MHz wide IF that was digitized and processed with DSP and FIR filters. It included digital combiner to provide the best possible data recovery and sold for around $80,000, depending on the options installed.

the system aboard the ISS was a modified 700 series, that was mounted in one of the aluminum rack modules and powered directly from the 48 volt power buss aboard the ISS. That receiver used a DAC as a volume control, and it worked quite well. The video level was controlled by a DAC to provide the control voltage for a four quadrant multiplier to give a very linear 39 dB range, and an additional 24 dB gain stage extended it to 63 dB in .1 dB steps. We went that route because a few customers needed more than the standard 20 MHz video bandwidth. The other modifications were to allow the unit to be controlled by a computer system aboard the ISS.

My work is in orbit aboard the ISS, used by NASA to communicate with every satellite the US has in orbit, NOAA receives their weather satellite photos from their LEO satellites with a turn key package we built for their Wallops Island facility, and the ESA bought two complete systems for their space program. One is fixed at the launch site, while the other is in a larger communications trailer they tow to a remote site during a launch, along with a lot of military tracking systems. All you ever do is post stupid ideas and bad information. Keep it up. Anyone who knows electronics sees that you are a fraud. You make vague references about your 'job', but don't tell where you work because you don't want them to see the way you look online.

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Reply to
Michael A. Terrell

Er, this isn't alt.personality.ego-massage you know?

We're happy for you, really, but you may injure yourself by blowing your own trumpet so hard.

Reply to
Flyte

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Two whole posts under your belt and its already "we"?

Oh, well, at least you\'ve learned to bottom post.
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Reply to
John Fields

Read some of Jamie's posting history if you want to see 'ego'.

Tell us if you've ever done anything other than complain. I am near retirement age and worked in electronics from the time I was 13. i will not suffer fools gladly, and let them influence people who don't know they are idiots or liars. There are a lot of others on this and the other electronics newsgroups who are tired of idiots and trolls trying to confuse people who have real questions. If you prefer to have Jamie lead you astray, enjoy being lost.

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Reply to
Michael A. Terrell

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