Soluciones y Tecnologías de Control Embebido S.A.P.I. de C.V.
www.sepradel.com [email protected] +52 1 833-389-4054
3
•
The input Pulse counter
Input
The input is based on a 50
Ω
impedance BNC connector; TTL type (with extended capacity for
pseudo-square pulses and up to 10VDC). The input has over-voltage protection, so momentary
input pulses outside the allowed range will be virtually short-circuited to prevent them from
entering the rest of the delay device modules.
An input stimulus can be the positive or negative edge of a square, triangular, or square-like
pulse, or a packet of input pulses, the amount of which is defined with the input counter option.
The input supports TTL pulses with voltages between 0V and 10V. This allows the direct
interconnection of a module for detecting short laser pulses, which although the output signal of
said photodiode module is analog, for being of short duration (in the order of tens of 10
-9
s), it is
closer to Virtually a square or triangular pulse with a very steep rising and falling edge, so it will be
detected by the delay generator without major complexity.
Outputs
Like the input, the outputs are also BNC and TTL type, with a nominal impedance of 50
Ω
,
protection against short circuits and external overvoltages. They have a current capacity of 80 mA
and a maximum output voltage of 5VDC.
Internal Structure of the Delay Pulse Generator
The following figure shows in a simplified way the structure or internal logic of the Pulse
Generator with Programmable Delays DG-3O1I-17.
3
The function of Counting pulses at the input will be detailed later, but basically allows the Device to
activate the outputs only when a certain number of pulses have arrived at the input. This is useful, for
example, in multipulse lasers, to trigger the spectrometer only with the arrival of the nth laser pulse and not
only in the first one. Another use is to activate a spectrometer and a Q-switch every certain number of flash
lamp shots, so our laser would maintain a high frequency of flash flicker while the Q-switch and the
spectrometer only activate at a submultiple of the flash lamp frequency.
