FROM EDN EUROPE: Arbitrary generator simplifies operation with 'scope-like display

Tektronix has added to its range of arbitrary waveform generators with a model in what the company terms the "value" segment of the market (Picture). The AFG 3000 arbitrary/function generators are designed to make this class of instrument easier to operate, and add pulse generation capability. A new addition is a large graphical display that shows a waveform representing the output of the generator—although the displayed waveform shows the output that the user's front-panel setting should produce, not a measured waveform as an oscilloscope function would produce. Users create waveforms either graphically or by mathematical definition, using a package called ArbExpress; they can also edit and re-output captured waveforms transferred from an instrument such as a 'scope using the same software. The instrument's look-and-feel is similar to the front panel of Tektronix' TDS 1000/2000/3000 oscilloscopes.

Six models comprise the range, in single- and dual-channel versions. Frequency coverage varies by model, from 25 up to 240 MHz, at a maximum sampling rate of 2 Gsamples/sec. Pulse generation is to a maximum of 120 MHz, and arbitrary waveform samples are 14-bit resolution. The two channels can be completely independent or identical with variable phase offset. A range of modulation types is supported, including AM, FM, PM, FSK, PWM, and Burst. PC/storage interfaces are LAN and USB, with GPIB as an option.

At the heart of the generators is an ASIC that Tektronix calls a generator on a chip; it includes Direct Digital Synthesis (DDS) circuitry, waveform memory, signal modulation, sweep generator, noise source and DAC. The signal-generation circuit comprises eight identical modules running at 250 MHz each and that are multiplexed to achieve the 2 Gsamples/sec sampling rate. The DDS circuit has separate operation modes for standard, arbitrary and pulse waveform generation, including variable period and independently adjustable rise and fall times. Inputs for external trigger and reference clock enable the synchronisation of multiple instruments. The company also provides an external modulation input to operate all modulation modes via an external signal. Prices of the series will range up to about $10,000.

Tektronix, www.tektronix.com.