BSA Flow Software Installation and User's Guide - CSI

Dead Time It can used to avoid over-sampling the velocity information, and thereby
eliminate velocity bias. It is typically used when the required result is the
moments of the velocity distribution (mean, RMS, skewness and flatness). It
has the additional advantage of reducing the data file size, compared to the
other modes.
Please consult chapter 8 for more information on how to use the different
modes.
Burst is used when the photo-detector signal consists of discrete bursts from
seeding particles, and when a high data rate is required. There is one
measurement per detected burst, producing arrival time, transit time and
velocity information.
Continuous This mode is used if the Doppler signals appear as quasi-continuous signals.
This is typically the case when measuring the velocity of a solid surface. In
continuous mode, the burst detector is not used, and the photo-detector
signal is processed continuously. Several measurements can be taken during
each burst. Auto-adaptive record length is not applicable in this mode.
In Dead time mode, the time axis is divided into intervals. In each interval,
only the first Doppler burst is processed. The interval is specified in the
Dead-time property.
Duty cycle Duty cycle is only applicable to Continuous mode. The duty cycle is
defined as the percentage of records transferred to FFT processing. It is used
in experiments with a very high data rate to prevent an input buffer
overflow. Possible values are shown in the drop down list.
Dead-time It is only applicable to the Dead Time data collection mode and defines the
length of the time interval, from which to process the first burst.
Calibration mode (PDA only - available with Particle Size add-on).
The phase calibration can be made automatically whenever needed, always
before acquiring or never. The automatic mode is selected by defaults and
means that the calibration will be carried out when the velocity span, the
center velocity, the gain or a high voltage is/are changed.
40MHz frequency shift, Variable frequency shift, Variable shift
frequency
These properties control the signals on the Bragg cell connectors at the rear
panel of the BSA. These can be used individually or in combination.
Note The 40 MHz output includes DC supply compatible with Dantec Bragg cells.
The Var. output supplies a 1.8Vpp AC and 12V DC.
The connector 40 MHz is used with LDA optics using 40 MHz optical
frequency shift, such as most Dantec FiberFlow and FlowLite systems, and
in dual-Bragg cell systems with one cell operating at 40 MHz.
The connector Var. is used with LDA optics using other drive frequencies to
the Bragg cell, and in dual-Bragg cell systems with the first Bragg cell
operating at 40 MHz.
5-16 BSA Flow Software: Project explorer objects