NOVATECH INSTRUMENTS

PC Compatible 34 MHz Direct Digital Synthesizer

Model DDS4pc

Photo
Last Modified January 10, 2001

The DDS4pc Direct Digital Synthesizer is a 34 MHz Signal Source on an ISA Bus Card compatible with PC AT and later computers. It provides both sine and clock output signals up to 34 MHz in 0.02 Hz steps. The DDS4pc comes with a C-language program that runs under DOS and 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.


Specifications

OUTPUTS

TYPES: Sine and TTL Simultaneously
IMPEDANCE: 50 ohms
FREQUENCY: 1 Hz to 34 MHz in 0.02 Hz steps

SINE AMPLITUDE

AMPLITUDE: Approx. 1 Vrms into open circuit, 0.5 Vrms into 50 ohms
FLATNESS: 3 dB from 5 Hz to 34 MHz referenced to 1 MHz, stable to 0.5 dB from 20 to 30 C
AUDIO FREQUENCY FLATNESS: 0.1 dB from 20 Hz TO 20 kHz, referenced to 1 kHz

TTL AMPLITUDE:

VOL: 0.5 V max, VOH: 2.5 V min., with 30pF load below 25 MHz, <5 ns rise and fall times

SINE OUTPUT ATTENUATION

0 to 70 dB in 10 dB steps , 0.5 dB

CONTROL

Output frequency, sinewave attenuation and clock source are set by five 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.

ACCURACY AND STABILITY

Accurate to < 10 ppm at 25 2 C, 24 hrs
Stable to 10 ppm/year, 20 to 30 C

SPECTRAL PURITY (Typical, 0 dB Attenuation )

PHASE NOISE:

SPURIOUS:

HARMONIC:

SWITCHING TIME

NOVATECH supplied software allows the frequency to be changed in approximately 1 ms to 10 ms minimum time increments, depending on the performance of the user's PC, and automatically adjusts for the user's PC system speed. Attenuation changes in 10 ms maximum, with maximum of 10 changes per second. Frequency switching time is limited by the ISA bus speed.

POWER REQUIREMENTS (From Slot)

+5 V @ <1 A, 12 V @ <100 mA

CONNECTORS

BNC's provided for Sine Output and TTL Output

PRICING

Click here to see our price sheet.


Novatech Instruments , Inc.

P.O. Box 55997
Seattle, WA 98155 USA
206.301.8986, ntsales@eskimo.com, FAX 206.363.4367
Return to Homepage: http://www.eskimo.com/~ntsales.html
Technical Questions: novatech@eskimo.com