help for F-V converter (pc-machine)

hello all,
our project involves converting the square pulses from PC to the readable DC voltage.this gives the spindle motion and position of the CNC machine.
so we have a software which generate square pulses and send them through pin6 of parallel port.all we need is converting this signal to analog DC voltage.
we tried several chip like LM331....but its not working.we can't use LM2917 as its not so precise.(chip shld be able to give as min as possible voltage against the input frequency)
the output we need is like for 1Khz--->1volt
2Khz---->2volt
so guys is there any other chip which can carry out this task efficiently?
if any one has idea abt it pls help
thanks

it can be done with software PWM, no need for any chip

I can't get the LM331 working properly either . There must be something missing, it should be ideal once we figure out what it is

Use TC9400 from microchip. It is basicly a V/F convertor but also works as F/V convertor and generates an output voltage linearly proportional to the input frequency waveform. the frequency range is from DC to 100kHz,You can find the datasheet and application notes in the following URL

**broken link removed**

penoy_balut said:

it can be done with software PWM, no need for any chip

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thanks.can u give me some more details of it.

@kamdy
thanks.i'll try this.(have u tried it before,just curious)

@kamdy
thanks.i'll try this.(have u tried it before,just curious)
Today 01:31 PM

Yes I have used in a project to convert RPM to voltage

Yes I have used in a project to convert RPM to voltage

Click to expand...

u mean tachometer?

and in data sheet i saw some more circuits along with F-V converter.its abt ripple control etc.do we really need all that stuff or just the basic circuit(see attachment) will serve the purpose.