Sine wave generation

[PK]

Hi grp, I want to generate three sine wave signals with harmonics
present in it with the help of D/A converter. Has anyone gone thru such
application?

I've searched lots of DACs, mostly analog devices has a wide range of
DACs.

I think I shud go for multichannel DAC, possibly 4.
14/16 bit resolution & 8/10 us settling time.

If someone has worked with DAC interfacing plz suggest ur ideas n
opinions.

Wht r other sine wave generation techniques? With the help of PWM also
we can generate bt it suffers in the accuracy levels.
BBye...

 

[[email protected]]

Hi grp, I want to generate three sine wave signals with harmonics
present in it with the help of D/A converter. Has anyone gone thru such
application?

I've searched lots of DACs, mostly analog devices has a wide range of
DACs.

I think I shud go for multichannel DAC, possibly 4.
14/16 bit resolution & 8/10 us settling time.

If someone has worked with DAC interfacing plz suggest ur ideas n
opinions.

Wht r other sine wave generation techniques? With the help of PWM also
we can generate bt it suffers in the accuracy levels.
BBye...

Ive done it with PWM before, it's actually easier to get high accuracy
than with a DAC. You didnt say what frequency range you wanted, so no
real answer is possible.

 

[Tom Bruhns]

For audio, it's pretty straightforward. You can use a DSP, FPGA, or
even a moderately fast microcontroller to generate the digital sine
samples. With fast enough processing, you can generate the fundamental
and the harmonics, or you can pre-store a cycle of the desired waveform
(with the desired harmonic content) and use table lookup in that
instead of the more usual sine table. You'd have to store a whole
cycle, I guess, instead of using the tricks with a sinewave where you
only need one quadrant stored. Also, interpolation will not be as easy
as with a pure sine. There are actually quite a lot of ways of
handling the details, and the "best" way will depend on just what
matters to you the most and what you can not worry so much about.

Look up "phase accumulator sine generation" as a start. You can also
do a recursive sine generation, but beware of roundoff errors slowly
changing the magnitude. The phase accumulator can be used to generate
harmonics: two times (a one bit shift of) the phase accumulator value
is the second harmonic, add the original to the shifted and get the
third, two bits shift is fourth, fourth plus original is fifth, third
shifted one bit is sixth, ... (in case you don't have hardware
multiplication available). Modern audio DACs are cheap, easy to use,
and offer the possibility of good accuracy.

PWM and similar techniques are certainly possible, though I'd be
inclined to just let a delta-sigma converter do the PWMing for me...

Cheers,
Tom

 

[Robert Baer]

Hi grp, I want to generate three sine wave signals with harmonics
present in it with the help of D/A converter. Has anyone gone thru such
application?

I've searched lots of DACs, mostly analog devices has a wide range of
DACs.

I think I shud go for multichannel DAC, possibly 4.
14/16 bit resolution & 8/10 us settling time.

If someone has worked with DAC interfacing plz suggest ur ideas n
opinions.

Wht r other sine wave generation techniques? With the help of PWM also
we can generate bt it suffers in the accuracy levels.
BBye...

Some HP waveform generators used a classical square / triangle
generator, and a diode function generator to turn the triangle to a sine
wave.
Very effective and decently low distortion; only the peak had a
"problem".
For a cleaner sinewave, one could use he classical analog computer
solution to the second differential.
Or use the classical wien bridge.
These last two methods can be made to produce extremely low distortion.

 

[Genome]

Hi grp,

h pk wt kg m d i c h.

f o

DNA

 

[[email protected]]

Hi grp, I want to generate three sine wave signals with harmonics
present in it with the help of D/A converter. Has anyone gone thru such
application?

What harmonics do you need? A plain square wave will have the odd
harmonics with amplitudes that reduce as 1/n. (The fifth harmonic has
an amplitude 1/5 of the fundamental, the seventh is 1/7, etc.)

I can guarantee that any method that you use to produce sine-like
signals will have some harmonic content. (For a signal to only have
energy at exactly one frequency the signal has to exist for all time.
Any modulation of the signal, like turning it on or off, will cause
some harmonics.) So, what is it that you actually want?

 

[Don Lancaster]

Hi grp, I want to generate three sine wave signals with harmonics
present in it with the help of D/A converter. Has anyone gone thru such
application?

I've searched lots of DACs, mostly analog devices has a wide range of
DACs.

I think I shud go for multichannel DAC, possibly 4.
14/16 bit resolution & 8/10 us settling time.

If someone has worked with DAC interfacing plz suggest ur ideas n
opinions.

Wht r other sine wave generation techniques? With the help of PWM also
we can generate bt it suffers in the accuracy levels.
BBye...

http://www.tinaja.com/magsn01.asp


--
Many thanks,

Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email: [email protected]

Please visit my GURU's LAIR web site at http://www.tinaja.com

 

[[email protected]]

h pk wt kg m d i c h.

f o

DNA

xlnt !

-j