The DDS3pc Direct Digital Synthesizer is a 12 MHz Signal Source on an ISA Bus Card compatible with PC AT and later computers. It provides both sine and clock output signals from 2 Hz to 12 MHz in 2 Hz steps. The DDS3pc comes with a C-language program that makes it easy for the user to set frequency and attenuation. The user can automatically sweep through a set of frequency, attenuation and dwell time settings stored in a text file using the supplied software.
Output frequency, sinewave attenuation and clock source are set by four bytes of data in I/O address space starting at the base address set by an on-board switch (0338 Hex default). A C-language program is provided as an example. Both compiled and source code files are included. This program allows control of up to 1000 frequencies and amplitudes in the Command File mode or allows interactively setting frequency and amplitude.
The DDS3pc contains an internal 33.554432 MHz quartz crystal oscillator. It also accepts an external TTL/CMOS clock input of up to 40 MHz. The supplied program allows users to select the external input as the DDS3 PC system clock. An external clock will change the DDS3 PC step size in proportion to its ratio to the internal system clock. External output filtering may be needed when using an external clock lower than 33.55 MHz.
NOVATECH supplied software allows frequency to be set in nominal 1 mS time increments and automatically adjusts for PC system speed. Attenuation changes in 10 mS maximum, with maximum of 10 changes per second.
Click here to see our price sheet.