what are this 4 diode perform based on the circuit?

[rockyou]

hi.can anybody explain for me that why there are 4 diode on the circuit?what are they do actually?my question how the diodes work here, is this just a clipper circuit?

Anyway I would appreciate it if someone could explain to me how the circuit work, or at least just the name of the circuit. Searching sine wave shaper blindly these past few days didnt yield much result. Thank you

 

[betwixt]

The non-linear V/I characteristic of the diodes is being used to progressively compress the peaks of the triangle wave so it approximates to a sine wave.

Brian.

 

[rockyou]

thank you for the answer.thank you brian.

in your opinion,do you think this circuit is variable frequency and variable amplitude?

 

[betwixt]

It is amplitude only.

There will inevitably be a change in amplitude of output signal as the frequency increases because of limitations of the diodes and op-amp but the schematic isn't designed to utilize that effect and it probably wouldn't show until the frequency was quite high.

Brian.

 

[rockyou]

oh,ic.what if i change the frequency of the triangle input so the sinewaveform frequency change accordingly?

 

[betwixt]

You are compressing the peaks of the triangle more than the lower parts, that's why they become rounded and more like a sine wave. The sine waveform is therefore at exactly the same frequency as the triangle one. If you shift the triangle frequency, the sine will match it.

Brian.

 

[E-design]

Variations of this method of wave shaping can be found in many low cost function generators.

 

[rockyou]

Brian.once thank you again.

E-design,i had found many of this wave shaping,but dont know which to choose.

Added after 4 minutes:

any1 know how to perform the harmonic sine wave?

 

[E-design]

Normally multiple sections are used to reduce distortion of the resultant sine wave.

 

[Audioguru]

What is a"harmonic sinewave"?

Is the opamp a lousy old 741 that has poor performance above only 9kHz?
Or is it a modern opamp that works perfectly up to 100kHz?

 

[rockyou]

What is a"harmonic sinewave"?

Is the opamp a lousy old 741 that has poor performance above only 9kHz?
Or is it a modern opamp that works perfectly up to 100kHz?

FOURIER COMPONENTS OF TRANSIENT RESPONSE V($N_0017)



DC COMPONENT = 7.061931E-03

HARMONIC FREQUENCY FOURIER NORMALIZED PHASE NORMALIZED
NO (HZ) COMPONENT COMPONENT (DEG) PHASE (DEG)

1 5.000E+01 1.532E+00 1.000E+00 4.611E+00 0.000E+00
2 1.000E+02 1.217E-02 7.946E-03 1.120E+02 1.027E+02
3 1.500E+02 7.646E-02 4.991E-02 -1.786E+02 -1.925E+02
4 2.000E+02 1.190E-02 7.767E-03 6.235E+01 4.391E+01
5 2.500E+02 4.079E-02 2.663E-02 2.834E+01 5.282E+00
6 3.000E+02 8.867E-03 5.788E-03 4.568E+01 1.802E+01
7 3.500E+02 1.091E-02 7.121E-03 -1.371E+02 -1.694E+02
8 4.000E+02 9.392E-03 6.131E-03 2.051E+01 -1.638E+01
9 4.500E+02 1.065E-02 6.950E-03 3.595E+01 -5.548E+00


TOTAL HARMONIC DISTORTION = 5.910534E+00 PERCENT


JOB CONCLUDED

TOTAL JOB TIME .28



this is the output file for sinewaveform,and i want it to simulate to show how is the signal pattern.

Added after 9 minutes:

Normally multiple sections are used to reduce distortion of the resultant sine wave.

ya,im looking for this answer but i dont how should i simulate on th pspice.
because based on my circuit,it is not purely sine waveform,so i want to know how good is this sinewave and my supervisor ask me to perform harmonic on this sinewave generator.im stuck on this harmonic.