Electronics -- Oscillators / Clock Generators
Extremely simple 8bit, 2MS/s direct digital synthesis board: Basically it's a microcontroller conntected to a DA converter. Includes an output amplifier and an optional USB connection.
A digital noise source produces seemingly random low/high pulses.
Applications include testing of transmission lines and generation of
analog noise using an additional filter stage.
A tiny variable clock generator: No precision thingy,
compared to crystal stabilized oscillators but reasonable for enough
"quickly need a square wave" applications.
When testing digital circuits, especially microcontroller-based ones, the above wave generator is not the device of choice. For reliable clock cycle counting (to see how many clock cycles some instructions take), you need a very stable and accurate clock frequency, preferrably 100kHz, 1Mhz or so. For my Atmel microcontroller works, I needed some clock generator with the following properties (most of which the above device does not fulfill):
There was another critical aspect: I needed the device now, quickly, preferrably with those parts available at home. After one day for the design and the manual PCB layout, I came up with this precision clock generator which I actually made to work using one additional day.
Intersil's ICL8038 is a simple VCO (voltage controlled oscillator) chip which is "not recommended for new designs" but still available and relatively cheap. Due to its wide spread application it is easy to obtain and most likely still available in the future. It is capable of producing sine, triangle and square wave output with a frequency up to several hundred kHz.
I used the ICL8038 to build a simple oscillator which should fulfill the following requirements:
After some experiments, I built an ICL8028-based Oscillator (follow the link for more info; currently this is the 3rd revision dated 09/2004).