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SensL © 2011
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USER MANUAL
HRM-TDC
SensL © 2011
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> Hrm-tdc System Description > Hrm-tdc Specific Feature Overview
HRM-TDC TYPICAL APPLICATION
Figure 4 Example application using the HRM-TDC
Note:
Figure 4 shows a typical application setup utilizing a wide range of the HRM-TDC features. In this example the
experiment is a TCSPC application where a LASER is stimulated by a clock and the time before a photon is detected
is measured. The LASER is continually pulsed at a fixed frequency (typically 50MHz). The LASER output will affect a
setup resulting in a photon arriving at the APD Detector such as the SensL PCDMiniSL. It is assumed that the rate
of photons arriving at the APD is far less than the rate of the LASER pulses. As a photon is not guaranteed for each
cycle of the LASER, the system will use the photon event as the start of the TCSPC process and a delayed version
of the LASER pulse as the stop signal. This technique avoids countless dead cycles and simplifies the associated
electronics required for recording the events.
The HRM-TDC module measures and records the time delay between clock and photon from the experiment and
uploads the results, in real time, to the host computer via the USB interface. In some cases the experiment will
involve multiple TCSPC curve measurements as the experiment changes the settings of external equipment. The
programmable I/O of the HRM-TDC module is used to cater for such applications. The external equipment, such
as a microscope, can indicate its X,Y movement to the HRM-TDC module allowing multiple curves to be measured.
Alternatively, the HRM-TDC module can be programmed as outputs to control the external equipment and cause
the actual X,Y positioning of the equipment.
HRM-TDC SPECIFIC FEATURE OVERVIEW
The flexibility of the HRM-TDC allows it to be used in a variety of modes. The following are examples of how the SIE
software utilizes the START and STOP signals in different ways to cater for different applications.