This range of synthesised programmable arbitrary waveform generators has the following features: • 1, 2 or 4 independent arb channels • Additional DC to 50MHz fixed amplitude sine and squarewave outputs on 2- and 4-channel instruments • Up to 100MHz sampling frequency • Sinewaves up to 40MHz, squarewaves up to 50MHz • Output level 2.5mV to 10Vp−p into 50Ω with 12 bit vertical resolution • 1M points horizontal resolution per channel • Compact Flash card for non−volatile waveform memory • Waveform linking, looping and sequencing • Interchannel triggering, summing, modulation and phase control • GPIB, RS232 and USB interfaces The instrument uses a combination of direct digital synthesis and variable clock techniques to provide high performance and extensive facilities in a compact instrument. It can generate a wide variety of waveforms between 0·1mHz and 50MHz with high resolution and accuracy. Arbitrary waveforms may be defined with 12 bit vertical resolution and from 8 to 1048576 horizontal points. In addition a number of standard waveforms are available including sine, square, triangle, ramp and pulse. Arbitrary waveforms may be replayed at a user specified waveform frequency or period, or the sample rate may be defined in terms of period or frequency. Alternatively, an external Arb clock may be used at frequencies up to 50MHz. Extensive waveform editing features between defined start and end points are incorporated, including waveform insert, point edit, line draw, amplitude adjust and invert. More comprehensive features are available using the arbitrary waveform creation software supplied. This is a powerful Windows−based design tool that enables the user to create waveforms from mathematical expressions, from combinations of other waveforms, freehand, or using a combination of all three techniques. Waveforms created in this way can be downloaded via the RS232, GPIB or USB interfaces or transferred directly to the generator on a removable memory card written to by the PC using the USB-connected card reader/writer provided. Up to 500 different waveforms may be stored with the length and name specified by the user; the total size of all the waveforms stored is limited only by the size of the memory card. Waveforms may be linked together to form a sequence of up to 1024 steps. Each waveform may have a user defined repeat count from 1 to 32768. All waveforms can be swept over their full frequency range at a rate variable between 1 millisecond and 15 minutes. Sweep can be linear or logarithmic, single or continuous. Single sweeps can be triggered from the front panel, the trigger input, or the digital interfaces. A sweep marker is provided. Amplitude Modulation is available for all waveforms and is controlled from the previous channel or from an external generator via the MODULATION input socket. Signal Summing is available for all waveforms and is controlled from the previous channel or from an external generator via the SUM input socket. All waveforms are available as a Triggered Burst whereby each active edge of the trigger signal will produce one burst of the carrier. The number of cycles in the burst can be set between 1 and 1048575. The Gated mode turns the output signal On when the gating signal is true and Off when it is false. Both Triggered and Gated modes can be operated from the previous or next channel, from the internal Trigger Generator (0.005Hz to 100kHz), from an external source (dc to 1MHz) or by a key press or remote command. Any number of channels can be synchronised with user defined phase angle between channels. This can be used to generate multi−phase waveforms or synchronised waveforms of different frequencies. The signals from the REF IN/OUT socket and the SYNC OUT socket can be used to synchronise two instruments where more than 4 channels are required. The generator parameters are clearly displayed on a backlit LCD with 4 rows of 20 characters. Soft−keys and sub menus are used to guide the user through even the most complex functions. All parameters can be entered directly from the numeric keypad. Alternatively most parameters can be incremented or decremented using the rotary control. This system combines quick and easy numeric data entry with quasi−analogue adjustment when required. The generator has RS232, GPIB and USB interfaces as standard which can be used for remote control of all of the instrument functions or for the down−loading of arbitrary waveforms. As well as operating in conventional RS232 mode the serial interface can also be used in addressable mode whereby up to 32 instruments can be linked to a single PC serial port.