November 7, 2011. Novatech Instruments Inc. has introduced the Model 425A, a precision 350-MHz DDS signal generator packaged in a small shielded table top case. The 425A generates sine wave, LVDS, and LVCMOS output signals simultaneously. The generated sine-wave output frequency is directly programmable in 10 µHz steps from 250 kHz to 350 MHz and includes a built in prescaler and divider for generating low-jitter LVCMOS clock signals down to less than 2 Hz.
The 425A uses the high-performance Analog Devices Inc. AD9912 DDS IC, which has 48-bit frequency tuning, 14-bit phase adjustment, and a 14-bit reconstruction DAC. The high resolution DAC enables the 425A to achieve low harmonic and spurious distortion. In addition, the 425A has 10-bit Amplitude control and an internal 1.5-ppm temperature compensated crystal oscillator (TCXO) that can be phase locked to an external 10-MHz reference. Locking to a reference gives the 425A the same stability and accuracy as the reference. When multiple 425A are locked to the same reference, they remain phase synchronous. A direct clockinput up to 1000 MHz can also be selected.
The 425A is controlled by short text commands to the 425A serial port. Model SOF8_425 PC software is included and provides menu selections for command generation along with the ability to run a sequence of commands from a user created file. The Model 425A sells for $1,495 each and is available from stock.