CDS 53A-241 Arbitrary Waveform Generator

The Aeroflex / Tektronix / CDS 53A-241 Arbitrary Waveform Generator (ARB) Card is a printed circuit board assembly for use in a JcAIR 53/63 Series System. The card produces a series of voltage samples to create precise sinusoidal, triangular, square, and user-defined arbitrary waveforms. The ARB Card produces an analog output of +/-5.11 V in digital steps with 10-bit resolution (10 mV/step) when driving a 50-Ohm load, or +/-10.22 V (20 mV/step) when driving a high-impedance load.

Eighteen different sample update rates are programmable, covering a 6.5-decade range from a high speed of 2 MHz to a low speed of 4 Hz. Up to 8,192 10-bit voltages may be programmed into the on-card memory. The memory may be partitioned into two 4K-word blocks or a single 8K-word block. When partitioned as two 4K blocks, one memory partition may be updated while the other is transmitting.

The waveform in each partition may be of any length up to 4,096 samples. Each waveform may be independently programmed to repeat from 1 through 99 times, or continuously. The two partitions may also be chained together, and the chained composite of the two waveforms may be programmed to repeat from 1 through 99 times, or continuously.

Breakpoints may be programmed in any nonconsecutive memory locations. A breakpoint will temporarily pause the waveforms until retriggered by software or until an external hardware TTL trigger.

Memory locations are easily programmed by a string of numeric ASCII characters which directly represent the voltage output for that sample. An editing capability is provided to allow changing of individual points in the waveform without requiring a complete reloading of memory. To allow high-speed downloading of waveforms from the system controller (calculator or computer) under DMA control, the ARB Card can transfer characters at a 500-kHz rate. Memory loading has an auto-increment capability so that only the starting waveform address has to be programmed at the beginning of a block waveform load, further optimizing the speed of waveform updates.

Three auxiliary inputs are included on the card to allow use of an external clock, up to 2 MHz, to trigger the waveforms on an external input, and to externally gate or enable the clock. Two auxiliary outputs provide a clock at the programmed sample rate and a synchronization pulse at the end of waveforms in each memory partition.