- Labs project
LF Signal Generator DIL-Module with Spectral Input
January 12, 2015
Some years/decades ago, there were nice chips to generate analogue signals (sine, triangle, rectangle) which could form the base of LF-function generators and audio test equipment. Nowadays there are relatively cheap, powerful and well-equipped microcontrollers (ARM Cortex and so on), so why shouldn't we build our own flexible signal generator module? Put the micro and the needed circuitry around it on a tiny-sized breakout board with DIL-pinout (e.g 2x6) and you have a nice, flexible and easy-to-solder module for your projects. Of course, the module should come with our preprogrammed firmware for LF signal generation but of course everybody could reprogram the micro on the module him/herself to realize other functions too. I would like to suggest the following specs for our LF-signal generator module: * 1 LF-output (DAC) * LF-frequency range 0..50 kHz * Free waveform generation, waveform will be stored in a table with 4096 sample points * 3 analogue inputs, to control amplitude, frequency and offset by an analogue voltage 0...2,5 V * Digital parameter input over SPI * SPI waveform input, send the waveform data to the controller (waveform must be calculated by host microcontoller) * SPI spectral input, Send the spectrum to the signal generator (nice for audio synthesizers) * solder pins to be equipped with 50-mil-pinheader for reprogramming * module must be cheaper than 15 Euro Applications: * LF stand alone signal generator (for audio measurement and test and so on) * mobile and compact test device for general applications (handheld) * in-built test and calibration function for bigger devices * audio synthesizer (take 3 or more of these modules :-) ) Variety of solutions: We could realize this project with different microcontrollers/DSPs and software, just use one and the same pinout for our module, for instance 2x6: 3,3 V ---- GND AN IN1 ---- AN IN2 AN IN3 ---- AN OUT SCK ---- DIG OUT ("READY") MOSI ---- MISO GPIO ---- GPIO (for test and debugging) A could even start a contest, and the module with the best specs and/or the cheapest one wins.
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