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Multi-trigger digital delay generators A new development are digital delay generators that have gating and external triggering, dual or multi-trigger capabilities. The gate allows the user to enable outputs and/or triggers with an electronic signal. Some units have gate or trigger capabilities using a single or separate connectors. Dual or multi-trigger digital delay generators have several input triggers. These triggers can be selectively used to trigger any or all channels. The multi-trigger versions have programmable logic controller type functionality for incorporating interlocks, latches, dynamic delay adjustment and trigger noise suppression. Triggers are formed by logically combining the various inputs and outputs in And, Or, Xor and Negated forms. LIDAR applications use digital delay generators. A channel is used to trigger a laser. A second channel is used to provide a delayed gate for the data acquisition system. Gating allows regions of interest to be processed and stored while ignoring the bulk of unwanted data. A key issue in the design of DDGs is to generate triggered delays having crystal-oscillator precision but that are not quantized to the edges of the reference oscillator. There are a number of techniques used in digital delay generation. 1. The simplest scheme simply uses a digital counter and a free-running crystal oscillator to time intervals with 1-clock ambiguity, resulting in output edge jitter of one clock period peak-to-peak relative to an asynchronous trigger. This technique is used in the Quantum Composers and Berkeley Nucleonics instruments. 2. Triggered crystal, LC, or delay-line oscillators may be started at trigger time, and subsequently counted to make coarse delays, followed by an analog fine or "vernier" delay to interpolate between clock periods. An enhancement is to use a phase-locked loop to lock the startable oscillator to a more accurate continuous-running crystal oscillator using a technique that preserves the original trigger alignment. The classic Hewlett Packard 5359A Time Synthesizer used a triggered ECL delay-line oscillator which was synchronized to a crystal oscillator using a heterodyne phaselock technique; the technique was subsequently used in several Berkeley Nucleonics and LeCroy delay generators. Highland Technology uses a triggered LC oscillator and a DSP phaselock scheme. Jitter below 10 ps RMS relative to an external trigger can be achieved. 3. It is possible to design an analog-ramp delay generator, using a current source to charge a capacitor, that spans some tens of nanoseconds of delay range. One can then suspend the ramp current for some integral number of clocks, as timed by a crystal oscillator. The freezing of the ramp extends the range of delays without the requirement to synchronize the oscillator to the trigger. This technique is described in US patent 4,968,907 and was used in the Signal Recovery instrument. Low delay jitter is possible, but leakage current becomes a serious error contributor for delays in the millisecond range. 4. A flipflop-based dual-rank synchronizer can be used to synchronize an external trigger to a counter-based delay generator, as in case (1) above. It is then possible to measure the skew between the input trigger and the local clock and adjust the vernier delay, on a shot-by-shot basis, to compensate for most of the trigger. Jitter in the tens of picoseconds RMS can be achieved with careful calibration. This technique is used by Stanford Research Systems. Target Speed Simulator Based on Digital Delay Generator - US Dept of Transportation DOT HS 809 811 Section 4.10. "Experimental study of laser ignition of a methane/air mixture by planar laser-induced fluorescence of OH" "Measurement of local forcing on a turbulent boundary layer using PIV" "Repetitively pulsed ruby lasers as light sources for high speed photography applications" "Single photon detector module" "Programmable sequence generator with multiple outputs" Wavelength dependence on the elemental analysis of glass by Laser-Induced Breakdown Spectroscopy (1).pdf "Sync'ing, delaying and gating with multiple pulse trains" Categories: Electronic circuits Electronic test equipmentHidden categories: Articles lacking reliable references from October 2008 Wikipedia articles needing context from October 2008 Wikipedia introduction cleanup from October 2008 Articles that need to be wikified from October 2008 All articles that need to be wikified The e-commerce company in China offers quality products such as LED Spot Lamps Manufacturer , China LED Panels Lighting, and more. For more , please visit Flexible LED Strip Lights today!
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