hf gendet

Posted on Feb 6, 2014

I was lucky to use an HP33290A wave generator for my radio building projects, a fantastic instrument for generating all kind of signals up to 15MHz. Since I could not always rely on it and buying one would by far exceed my yearly hobby budget, I decided to build an HF generator instrument myself. It would not come close to the HP332

hf gendet
Click here to download the full size of the above Circuit.

90A in terms of performance, still it was the source of inspiration. I didn`t bother about the features I never used, but added a few of my own, the HF detector part being the most important. The instrument has two basic modes of operation: transfer mode and reflection mode, where the generator and the detector part are both used. It can obviously be used as a stand alone HF generator or HF power meter. It is moreover capable of sweeping a frequency band and of FSK modulation (hamradio standard). Its user interface consists of a rotary encoder switch, two buttons, and a 4 line by 16 character LCD. It as a COMport interface, to output a string of comma separated values for the frequency and power estimations. The circuit consists of three parts: the micro-controller, the HF generator and the HF power estimator. See here for the first part of the circuit diagram (controller and power supply) and here for the second part (HF generator and detector part). The micro-controller, an Atmega16 (see Atmel AVR 8-Bit RISC Homepage ) in a 40 pin DIL package and clocked at 12MHz, will serve the serial interfaces of the DDS and ADC chips (3 I/O lines each), the LM041L LCD module which includes a HD44780 driver chip (10 I/O lines), the user interface (rotary encoder and 2 buttons: 4 I/O lines), the relay drivers (2 I/O lines) and the COMport (2 I/O lines). A 5pin header, a few resistors, diodes and one transistor are permanently build into...

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