gres
Full Member level 4
First of all chips like 8038 doesn’t work as a arbitrart function generators. 8038 just can generate previously generated functions by VFO and signal shaping and conditioning. Difference between them and arbitrary function generators is that those second one can make signal that user want, with any shape. You need variable frequency oscillator with driving counter. Memory address is set by counter outputs. Memory need to be converted to analog signal. Most popular is ti use MCU that communicate with PC when receive a new program. Memory can be as (E)EPROM also.
Impossible is to create analog device that can create andy signal shape on output. That’s why generators are using digital technology.
Very simple analog generator can be made using oscillator, counter (eg.4017) , outputs with potentiometer. All wipers must be connected via diode to one point. Signal with opamp must be amplified by potentiometer so you can adjust amplitude of the output signal.
Schematics and working describe for ICL8038, MAX038 XR2206 you can find in datasheets.
Easy way to get sinewave with small distortion 0,05% is to take a square wave and feed via 8 order switched capacitor Butterworth lowpass filter IC.
Clock frequency needs to be 10 times higher than the output. You should set counter of 4 resistors CD4018 Johnson walking ring to make currently oversampled stepped sinewave. Then feed to 8 order switched capacitor butterworth, filter IC and you will get almost perfect sinewave.
Impossible is to create analog device that can create andy signal shape on output. That’s why generators are using digital technology.
Very simple analog generator can be made using oscillator, counter (eg.4017) , outputs with potentiometer. All wipers must be connected via diode to one point. Signal with opamp must be amplified by potentiometer so you can adjust amplitude of the output signal.
Schematics and working describe for ICL8038, MAX038 XR2206 you can find in datasheets.
Easy way to get sinewave with small distortion 0,05% is to take a square wave and feed via 8 order switched capacitor Butterworth lowpass filter IC.
Clock frequency needs to be 10 times higher than the output. You should set counter of 4 resistors CD4018 Johnson walking ring to make currently oversampled stepped sinewave. Then feed to 8 order switched capacitor butterworth, filter IC and you will get almost perfect sinewave.