New Transient recorder

model name TR 40-16bit-3U-opt.

The units have 32k memory, which can be configured by the user for shorter memory depths. The oversampling can also be configured by the user so that 20MHz, 10MHz, 5MHz, 2.5MHz and 1.25MHz sampling rates can be achieved while keeping the number of bins constant. Per default the units ship with a 16k tracelength and sampling speed of 40MHz.

options:

AP
separated inputs for analog and photon counting. Makes sense for APD users who also detect weak PMT signals (Raman signals, etc). One trigger source - two detectors (APD + PMT in photon counting). See also situations when this is not a good option

The black dip switch for the address selection also hosts the memory length selection, the following lengths can be selected.

memory depth678Sample16k Address 0
512OFFOFFOFFDip-Switch for 16k
1k ONOFFOFF
2k OFFONOFF
4k ONONOFF
8k OFFOFFON
16k ONOFFON
32k OFFONON

Transient recorder memory/range resol./repetition rate

sample rate10 2040MHz
memoryrange resol.157.53.75m
256 max. rep. rate31.255278kHz
max signal3.841.920.96km
512 max. rep. rate15.62639kHz
max signal7.683.841.92km
1Kmax. rep. rate7.811319.5kHz
max signal15.367.683.84km
2 Kmax. rep. rate 3.906.59.75kHz
max signal30.7215.367.68km
4 Kmax. rep. rate 1.953.254.88kHz
max signal61.4430.7215.36km
8 Kmax. rep. rate0.971.622.44kHz
max signal122.8861.4430.72km
16 K max. rep. rate0.480.811.22 kHz
max signal245.76122.8861.44km
32 K max. rep. rate0.240.400.61 kHz
max signal491.52245.76122.88km

with 10 kHz Laser the following trace lengths will work

sample rate10 MHz20 MHz40MHz
bins7501300 1950
tracelength (km)11.259.757.3

To work with these tracelengths set the DIP Switch 5, which turns the configurable tracelengths on, to ON.

AP Considerations

There are situations where the AP option looks like a economic good idea at first glance but the side effects are unwanted
  1. Depolarization: Use analog for the strong parallel and photon counting for the weak depol. channel. This works as long as you do not hit an strongly depolarizing ice cloud...
  2. N2 in water raman system: You typically send so much light out at 355 to see a water raman signal that the N2 which has 3 orders of magnitude more cross section would require a neutral density filter, where the expensive photons that your system emits, have to die to make the photon counting possible
  3. Daytime water raman (408nm): 408nm is not in the solar blind region any more, so typically your background signal goes up when the sun rises. If this signal background exceeds 60 MHz (roughly 1 mV with our PMT) the dead time correction for this is already significant. But more sadly most of your linear dynamic range of the photon counting has gone. Dead time correction after 90 MHz of observed count rate is far beyond where the photon counting dead time correction theory applies:
    (90MHz / 300MHz is not << 1)

Previous Transient recorder models

model name TR XX-YYY-opt.

XX= sample rate (for analog and photon counting), defines the ADC clock and photon counter readout cycle time.
20=20 MHz, standard (7.5 m range resolution)
40=40 MHz, for high resolution systems (3.75 m range resolution)

lower sample rate is possible, but it limits the max. average photon count rate (not the pulse pair resolution)

YYY= FIFO memory length, defines the max. signal length and the max. repetition rate
160= 16384 databins, standard, lidar signals up to 819.2µs or 122.88 km, max. rep. rate=300 Hz.
80= 8192 databins, lidar signals up to 409.6µs or 61.44 km, max. rep. rate=610 Hz.

for other combinations see list below.

options:

AP= separated inputs for analog and photon counting. Makes sense for APD users who also detect weak PMT signals (Raman signals, etc). One trigger source - two detectors (APD analog + PMT in photon counting).
opt.= optical trigger input.(Trigger source is a SMA Emitter). Additional galvanically decoupling. Only for very noisy laser sources (Excimer, flashlamp pumped Ti:Sapphire lasers). Our standard electrical trigger is already galvanically decoupled.
las= optical trigger with laser pulse as trigger source. Includes a photodiode and a fast Schmitt Trigger with variable threshold. Application: Passive Q-switched lasers (mini lidars).

Memory selection chart

Note: Starting from October 2009 all TR units will have a 64k memory, which can be configured by the user for shorter memory depths.

The black dip switch for the address selection also hosts the memory length selection, the following lengths can be selected.

memory depth678Sample
512OFFOFFOFFDip-Switch for 16k16k Address 0
1k ONOFFOFF
2k OFFONOFF
4k ONONOFF
8k OFFOFFON
16k ONOFFON
32k OFFONON
64k ONONON

Transient recorder memory/range resol./repetition rate

 model No.TR 10TR 20TR 40unit
sample rate10 2040MHz
memoryrange resol.157.53.75m
256 max. rep. rate15.6219.5322.32kHz
max signal3.841.920.96km
512 max. rep. rate7.81 9.7611.16kHz
max signal7.683.841.92km
1Kmax. rep. rate3.904.885.58kHz
max signal15.367.683.84km
2 Kmax. rep. rate 1.952.442.79kHz
max signal30.7215.367.68km
4 Kmax. rep. rate 0.971.221.39kHz
max signal61.4430.7215.36km
8 Kmax. rep. rate0.4880.610.69kHz
max signal122.8861.4430.72km
16 K max. rep. rate0.170.300.34 kHz
max signal245.76122.8861.44km


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