This project is to control Velleman PCGU1000 function generator with USB port. For communications trough USB, libusb unit is used. Directory of program, which uses this project, must contain file pcgu1000.bit (microcode for generator). This file can be also downloaded from Velleman's site. Currently it can control all parameters of generator like: on/off, -40dB, attenuator, offset, amplitude fine tune, filter, freq, sweep, waveform and so on. Standard signal waves like, e.g., sine, triangle and rectangle are available; other sine waves can be easily created. The signal waves are created in the PC and produced by the function generator via DDS (Direct Digital wave Synthesis). All outputs are galvanically separated from the PC in order to avoid measuring problems. Some features and specifications are:

• Frequency range: from 0.01Hz to 2MHz;
• Crystal-based stability;
• Low sine wave distortion;
• Two parallel output connectors for waveforms;
• TTL-level synchronization output;
• Standard waveforms: sine, square and triangle;
• Predefined library waveforms included: noise, sweep, ...;
• Amplitude range: 100mVpp to 10Vpp @ 1kHz// 600 Ohm load / 0V offset;
• Frequency setting resolution: 0.01%;
• With internal 40 dB attenuator (output divided by 100);
• Direct digital wave synthesis (DDS), stores up to 8192 of waveform points;
• Amplitude resolution: 0.4% of full scale;
• Offset: from 0 to -5V or +5V max. (resolution 0.4% of full scale);
• Vertical resolution: 8 bits (0.4% of full scale);
• Sample rate: 50MHz;
• Typical sine wave distortion (THD): < 0.08%;
• Output impedance: 2 x 50 Ohm.

This project, realized on freepascal with Lazarus, is a free software under the GNU GPL license and can thus be used and modified freely. For any further information click here.