Digital Pulse Generator Firmware Option

The digital pulse generator option adds 4 internal independent pulse generators with programmable duty cycle, output frequency, delay and number of loops. These pulse generators can be triggered by software, hardware trigger or can trigger each other allowing to form complex pulse schemes to drive external equipment or experiments. The pulse generators can be outputted on the existing multi-XIO lines or can be used to trigger the instrument internally.

Time resolution of the pulse generator depends on the cards type and the selected sampling rate and can be found in the technical data section:

• M2p/DNx.59/DNx.65 Series: programmed sampling rate. A sampling rate of 125 MS/s gives a time resolution of 1/125M = 8 ns. Fastest clock rate = 62.5 MHz (1 sample high + 1 sample low)
• M4i/M4x/DNx.22/DNx.44/DNx.66 Series: fraction of programmed sampling rate between 125 MS/s (8 ns) and 156.25 MS/s (6.4 ns). Fastest clock rate = 62.5/78.125 MHz (1 sample high + 1 sample low)
• M5i Series: fraction of programmed sampling rate up to 312.5 MS/s (3.2 ns). Fastest clock rate = 156.25 MHz (1 sample high + 1 sample low)

The pulse generator option is a firmware option and can be later installed on all shipped cards.

The pulse generator module provides a versatile timing synchronization interface between the acquisition/replay functionality of the card and external equipment. The module consists of four pulse generators, where each generator allows for (in)dependent generation of individual pulses, pulse trains or a continuous stream of pulses that can be output on a Multi-Purpose I/O Line, greatly enhancing the versatility of the XIO lines.

The versatile trigger capabilities allow for external or internal triggering. Moreover, the pulse generators can trigger each other, hence allowing for cascading of up to four pulse repetition time scales.
The outputs of the pulse generators are intrinsically synchronized to the card acquisition/replay functionality and its sampling clock, hence allowing for reproducible enabling or switching of external signals (e.g., for signal actuating). Other use cases might be pulse broadening, pulse delaying, or just pulse generation.

The generation of the pulse trains and timing signals is performed inside the FPGA of the card and is working in parallel to any other functionality of the card (such as data acquisition or replay), and hence not reducing the performance.

Feature Overview

• Four pulse generators are available
• Single-shot, multiple repetitions or continuous/infinite repetition of pulses
• Individual control of pulse length/duty cycle
• External or internal triggering/starting individually for each pulse generator
• Individual trigger delay per pulse generator allowing for phase shifting
• Internal cascading of pulse generators possible allowing up to four repetition time scales.

The “standard” modes of the multi purpose I/O lines are still available, as described in the “Multi Purpose I/O Lines” section. This chapter focuses on the additional functionality, available with the pulse generator firmware option installed.

The multi purpose I/O lines are available on the front plate and labelled with X0 (line 0), X1 (line 1), X2 (line 2) and X3 (line 3). As default these lines are switched off