designing of numerical controlled oscillator

[vlsi_vishal]

hi i am designing of numerical controlled oscillator for 5.9Ghz oscillation frequency but i dont understand how can i build lookup table for converting of numerical data into sinusoidal waveform,plz help me to build lookup table

 

[BradtheRad]

Suppose you want to divide the sinewave into 100 steps. You will create 100 lookup data.

Example, in BASIC programming language:

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Code Basic4GL - [expand]
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FOR J = 1 TO 100
 
K = J / ( 2 * PI )
 
LOOKUPDATUM ( J ) = SINE ( K ) * AMPLITUDE + DCV_OFFSET
 
NEXT J

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The lookup values incorporate your desired amplitude and DC volt offset factored in, but you can only do this if they never change.

To produce a 5.9 GHz sinewave, you will send the entire array of 100 lookup values once per cycle. Hence your device must do this at the very fast rate of 590 GHz. I have not heard of a microcontroller which can operate that fast.

Nor at 59 GHz which would allow a table of 10 lookup data.
Nor even at 5.9 GHz.

 

[dick_freebird]

At that frequency, any resolution at all is going to need an
exotic DAC. But the more sensible approach is a sine wave
oscillator, with the passives being numerically controlled.
Then the fundamental is the highest frequency you want,
and higher ones only need filtered out.

I don't know where you'd get a 5.9GHz*128 reference clock,
or the logic to run with it. Step back and look at practicalities.