OP AMP voltage multiplier

Ahmed Samir · Jul 3, 2003

Hi there

is it possible to realize a four quadrant voltage multiplier-for audio
signals- using an op amp or two?if so how and if it's not possible what's
the easist way to do it??

thanks very much
ahmed samir

Tony Williams · Jul 3, 2003

In article <be0b15$10tp6u$1@ID-36824.news.dfncis.de>,
Ahmed Samir <ahmdsamir@link.net> wrote:

is it possible to realize a four quadrant voltage multiplier-for audio
signals- using an op amp or two?if so how and if it's not possible
what's the easist way to do it??

AD633JN from Analog Devices. For best thd, use the
Y-inputs for the audio, and keep the ac input signal
below about 5Vrms.

--
Tony Williams.

Bill Sloman · Jul 3, 2003

Tony Williams <tonyw@ledelec.demon.co.uk> wrote in message news:<4c0c0fc3a1tonyw@ledelec.demon.co.uk>...

In article <be0b15$10tp6u$1@ID-36824.news.dfncis.de>,
Ahmed Samir <ahmdsamir@link.net> wrote:

is it possible to realize a four quadrant voltage multiplier-for audio
signals- using an op amp or two?if so how and if it's not possible
what's the easist way to do it??

AD633JN from Analog Devices. For best thd, use the
Y-inputs for the audio, and keep the ac input signal
below about 5Vrms.

The AD633 is clearly what the OP needs, but it isn't the op amp that
he is asking for, and it is probably worth mentioning that a
four-quadrant multipler is a non-linear device, and op amps - as such
- aren't designed for non-linear applications. After all, this is
cross-posted to sci.electronics.basics where you can't assume any
background knowledge of electronics.

-----
Bill Sloman, Nijmegen

Rene Tschaggelar · Jul 3, 2003

Ahmed Samir wrote:

Hi there

is it possible to realize a four quadrant voltage multiplier-for audio
signals- using an op amp or two?if so how and if it's not possible what's
the easist way to do it??

OpAmps cannot do this, have a look at the multiplying DACs.

Rene
--
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net

Bob Masta · Jul 3, 2003

On Thu, 3 Jul 2003 07:22:12 +0300, "Ahmed Samir" <ahmdsamir@link.net>
wrote:

Hi there

is it possible to realize a four quadrant voltage multiplier-for audio
signals- using an op amp or two?if so how and if it's not possible what's
the easist way to do it??

Not possible with an ordinary linear op-amp. The usual

approach uses an array of matched transistors (plus a
couple of op-amps). Try a Web search for 'Gilbert Multiplier'.

There are also Operational Transconductance Amplifiers
(OTAs) like the CA3080 and LM13600 that are often used
to create multipliers, but usually just 2-quadrant..

Depending on exactly what you are shooting for, there are
a number of tricky approaches, including diode ring (bridge)
multipliers, FETs as voltage controlled resistors, pulse width
modulation, log-antilog, etc. Tell us more about your application and
maybe we can pick out the simplest/best approach.

Bob Masta
tech(AT)daqarta(DOT)com

D A Q A R T A
Data AcQuisition And Real-Time Analysis
Shareware from Interstellar Research
www.daqarta.com

Vladimir Vassilevsky · Jul 3, 2003

Ahmed Samir wrote:

Hi there

is it possible to realize a four quadrant voltage multiplier-for audio
signals- using an op amp or two?

Everything is possible, but probably not worth to.
The accuracy and the distortion are going to be about 1% best to best.

if so how and if it's not possible what's
the easist way to do it??

I would advise to use DSP instead of messing with analog.

Vladimir Vassilevsky, Ph.D.

DSP and Mixed Signal Design Consultant

http://www.abvolt.com

Kevin Aylward · Jul 3, 2003

Vladimir Vassilevsky wrote:

Ahmed Samir wrote:

Hi there

is it possible to realize a four quadrant voltage multiplier-for
audio signals- using an op amp or two?

Everything is possible, but probably not worth to.
The accuracy and the distortion are going to be about 1% best to best.

if so how and if it's not possible what's
the easist way to do it??

I would advise to use DSP instead of messing with analog.

Vladimir Vassilevsky, Ph.D.

DSP and Mixed Signal Design Consultant

I reason your opinion is a obviously a bit biased here. I would guess
that the poster wants a *simple* solution. i.e. one without spending 6
months with development systems.

To the poster. Analog Devices SSM audio VCA parts are pretty good. They
used to be PMI ones, which used to be...

Kevin Aylward
salesEXTRACT@anasoft.co.uk
http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.

Precious Pup · Jul 3, 2003

Bill Sloman wrote:

... and it is probably worth mentioning that a
four-quadrant multipler is a non-linear device,...

And it is probably worth mentioning too that BS has never taken a Signals and Systems course, along with never
taking ECON101.

Show the following system to be either linear or non-linear:

The System
+---------------+
| |
in | /ŻŻŻ\ | out
x(t) O--------( X )---------O y(t)
| \___/ |
| | |
| | |
| O |
| cos(w_cˇt) |
+---------------+

Included and inside the system is a "4-Quad" multiplier.
Bonus points: Show the system to be either time-invariant or not.

Ben Bradley · Jul 3, 2003

In sci.electronics.design, "Kevin Aylward" <kevin@anasoft.co.uk>
wrote:

Vladimir Vassilevsky wrote:
Ahmed Samir wrote:

Hi there

is it possible to realize a four quadrant voltage multiplier-for
audio signals- using an op amp or two?

Everything is possible, but probably not worth to.
The accuracy and the distortion are going to be about 1% best to best.

With a diode 'ring modulator', maybe...

if so how and if it's not possible what's
the easist way to do it??

I would advise to use DSP instead of messing with analog.

You're just trying to drum up DSP business, aren't you?

Vladimir Vassilevsky, Ph.D.

DSP and Mixed Signal Design Consultant

I reason your opinion is a obviously a bit biased here. I would guess
that the poster wants a *simple* solution. i.e. one without spending 6
months with development systems.

To the poster. Analog Devices SSM audio VCA parts are pretty good. They
used to be PMI ones, which used to be...

MC1496 from onsemi.com, cheap, usable, still available in DIP (!),
less distortion than a diode ring modulator, and the company only used
to be one other company...

Kevin Aylward
salesEXTRACT@anasoft.co.uk
http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.

Jim Thompson · Jul 3, 2003

On Thu, 03 Jul 2003 13:53:53 -0700, Precious Pup
<barking@wrongtree.org> wrote:

Bill Sloman wrote:

... and it is probably worth mentioning that a
four-quadrant multipler is a non-linear device,...

And it is probably worth mentioning too that BS has never taken a Signals and Systems course, along with never
taking ECON101.

[snip]

480)460-2350 | |
| Jim-T@analog_innovations.com Fax

Bill Sloman · Jul 4, 2003

Jim Thompson <Jim-T@analog_innovations.com> wrote in message news:<ca79gvg362j458qvjprku0er6633itb77h@4ax.com>...

On Thu, 03 Jul 2003 13:53:53 -0700, Precious Pup
barking@wrongtree.org> wrote:

Bill Sloman wrote:

... and it is probably worth mentioning that a
four-quadrant multipler is a non-linear device,...

And it is probably worth mentioning too that BS has never taken a Signals
and Systems course, along with never
taking ECON101.

[snip]

How appropriate, "BS" ;-)

But "BS" has taken all the Commie and Socialism courses ;-)

...Jim Thompson

Ah. More jokes from primary school. Concentrate on electronics, Jim -
you are pretty good at that.

Oddly enough, I've not taken any Commie or Socialism courses either -
as with electronics, if there has been something I need to know I go
off to the library and read about it.

I used to be embarassed about my lack of formal qualifications, but
after you have supervised a few new graduates you get some idea of how
little of their coursework actually sticks, and I stopped worrying. It
never worried the IEEE at all.

I wonder if Peurile Pup has ever published anything in a refereed
journal - let alone had it cited.

-----
Bill Sloman, Nijmegen

Ben Bradley · Jul 4, 2003

In sci.electronics.design, "Ahmed Samir" <ahmdsamir@link.net> wrote:

i want to realize a frequency inversion circuit

audio signal from 300 to 3000hz, and the single tone at 3000hz

Oh, you want to make a "Voice Scrambler." This crude ASCII block
diagram should demonstrate it:

IN --->[300Hz-3kHz bandpass filter]--->[4-quadrant multiplier]--->out
^
|
|
3.3kHz sine wave

For the bandpass filter, cascade a simple R-C 300 Hz high-pass with
a two-pole or three-pole low-pass filter from Lancaster's "Active
Filter Cookbook."
This circuit will work for both encoding and decoding.

thanks

"Bob Masta" <no_spam@aol.com> wrote in message
news:3f041d46.1648407@news.itd.umich.edu...
On Thu, 3 Jul 2003 07:22:12 +0300, "Ahmed Samir" <ahmdsamir@link.net
wrote:

Hi there

is it possible to realize a four quadrant voltage multiplier-for audio
signals- using an op amp or two?if so how and if it's not possible
what's
the easist way to do it??

Not possible with an ordinary linear op-amp. The usual
approach uses an array of matched transistors (plus a
couple of op-amps). Try a Web search for 'Gilbert Multiplier'.

There are also Operational Transconductance Amplifiers
(OTAs) like the CA3080 and LM13600 that are often used
to create multipliers, but usually just 2-quadrant..

Depending on exactly what you are shooting for, there are
a number of tricky approaches, including diode ring (bridge)
multipliers, FETs as voltage controlled resistors, pulse width
modulation, log-antilog, etc. Tell us more about your application and
maybe we can pick out the simplest/best approach.

Bob Masta
tech(AT)daqarta(DOT)com

D A Q A R T A
Data AcQuisition And Real-Time Analysis
Shareware from Interstellar Research
www.daqarta.com

Precious Pup · Jul 4, 2003

Bill Sloman wrote:

Jim Thompson <Jim-T@analog_innovations.com> wrote in message news:<ca79gvg362j458qvjprku0er6633itb77h@4ax.com>...
On Thu, 03 Jul 2003 13:53:53 -0700, Precious Pup
barking@wrongtree.org> wrote:

Bill Sloman wrote:

... and it is probably worth mentioning that a
four-quadrant multipler is a non-linear device,...

And it is probably worth mentioning too that BS has never taken a Signals
and Systems course, along with never
taking ECON101.

[snip]

How appropriate, "BS" ;-)

But "BS" has taken all the Commie and Socialism courses ;-)

...Jim Thompson

Ah. More jokes from primary school. Concentrate on electronics, Jim -
you are pretty good at that.

Oddly enough, I've not taken any Commie or Socialism courses either -
as with electronics, if there has been something I need to know I go
off to the library and read about it.

Now that's an accomplishment. You can get deluded just fine without bothering with school.

I used to be embarassed about my lack of formal qualifications, ...

It isn't your formal qualifications you should be embarrassed about. You should simply be embarrassed about
being a persistant dumbass.

but
after you have supervised a few new graduates you get some idea of how
little of their coursework actually sticks, and I stopped worrying. It
never worried the IEEE at all.

I wonder if Peurile Pup has ever published anything in a refereed
journal - let alone had it cited.

Retard, I don't claim to be original, creative, smart, clever, and whatever else you fantasize yourself to
be. I don't really care. I try to get folks to give me money in exchange for effort/labor -- that's about
it.

Let me publish more right here for you:

Compare and contrast the two systems.

The System
+---------------+
| |
in | /ŻŻŻ\ | out
x(t) O--------( X )---------O y(t)
| \___/ |
| | |
| | |
| O |
| DC=2 |
+---------------+

The System
+---------------+
| |
in | |\ | out
x(t) O--------| >-------------O y(t)
| |/ |
| Op-amp set to |
| a gain of two |
+---------------+

Are these systems linear?

OP AMP voltage multiplier

Ahmed Samir

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