The High Speed Function Generator was published in the professional electronics section of the Aug 1996 issue of Electronics Australia, and has proven to be extremely popular. The kit is no longer available from any of the kit suppliers. The project is capable of generating 20MHz or greater Sine, Square, Triangle, and TTL waveforms.

Here is an extremely simple and low cost Sine/Square wave generator based on the Analog Devices AD9835 Direct Digital Synthesis (DDS) Generator chip. The frequency can be set for any frequency from 1Hz to 10MHz in 1Hz resolution steps! All this with three push buttons and a novel “sliding window” LED display. The controller chip is a Microchip PIC16F628.

The Max-80 function generator IC is specified to work to 20 MHz. So far, this unit works nicely to 50KHz. Since I seldom need signals higher than that, it has taken up a happy home on my workbench and further development is iffy at best. There are two basic approaches to controlling the frequency in this type of device. One way is to adjust the voltage to the IC manually and then read out the frequency with a counter. The problem here is you need to fiddle around with the control knob and while waiting for the one-per-second updates on the display. The other way is to set the display with the control knob and then have the circuit diddle the control voltage to the IC until it settles on that frequency. This is done by calculating the period for the target frequency and then using the PIC to read the pulse width. It then sends short correction pulses to an integrator which controls the IC.

Frequency Generator is an essential laboratory equipment for every electronic. It allows a variety of measurements and experiments. The module described here is based on high quality XR2206 IC and is extremely compact and inexpensive. Output frequency is from 1Hz to 1MHz. It provides sine, square and triangle waves around 1Hz to 1MHz, depending on the timing capacitors used. Over two Potentiometers the amplitude and frequency can be set. About trimmers can also have the purity of the sine signal and the offset of the output voltage can be changed.

Here's a universal 555 frequency generator with four frequency ranges that might be handy for building any projects that deal with frequencies. JP3 is a button used to switch the device on and off. The power supply (anything from 4-12V) is connected onto JP4. JP2 serves as the output for the signal with an attenuator, if we don't need the full strength (voltage) of the signal, only, say 3V of 5V. We can set the output value by R2. JP1 gives the full strength of the signal, with a current depending on the 555 type you use. R3 is used to set the frequency within a range chosen by the DIP switch S1. You can set which range of frequencies you want to use with a DIP switch. With it you enable or disable a capacitor which is hooked up into the datasheet circuit of the 555 chip.

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