LIF Digitizer

Overview

The LIF Digitizer reads in laser-induced fluorescence data. It is designed around two channels: one for the LIF signal and a second for a reference detector used to normalize by laser power. Each channel has a user-adjustable integration gate. When the reference channel is enabled, the integral of the LIF signal is divided by the integral of the reference signal during processing. The full time-domain LIF and reference traces are saved to disk during acquisition so they can be reprocessed later.

Note

The LIF data channel is hardcoded to channel 1 and the reference channel to channel 2.

Settings

The LIF digitizer shares its underlying configuration with the FTMW Digitizer, and most settings are exposed in the hardware dialog with inline labels and tooltips. Two differences are worth keeping in mind:

  • Multi-record and block-averaging modes are not used for LIF, even if the underlying device advertises them. Each shot is transferred to the host individually.

  • Because LIF traces are typically short and acquired at modest repetition rates, transfer-rate tuning is rarely necessary; pick a sample rate that resolves the gate region cleanly and leave the rest at their defaults.

Drivers

Virtual

A dummy driver used for development and for installs that only view archived data.

Spectrum Instrumentation M4i2211x8

The Spectrum Instrumentation M4i.2211x8 is a 2-channel high-speed digitizer with 500 MHz of analog bandwidth.

This driver requires the Spectrum Instrumentation spcm library to be installed on the host. See Library Status for installation details and to confirm that Blackchirp has located the library.

Rigol DS2302A

The Rigol DS2302A is a 2-channel, 300 MHz oscilloscope with a maximum sampling rate of 2 GSa/s. Unlike most digitizers Blackchirp supports, the sample rate cannot be set directly; the instrument chooses a rate based on the total record duration. The driver takes the user’s requested sample rate and record length, computes the corresponding time window, sets the horizontal scale to the nearest “nice” coarse value (1, 2, or 5 × 10N seconds), then queries the resulting sample rate and updates the record length to match.

The scope also offers no way to detect individual trigger events, so the driver polls for screen data on a timer. The polling interval is controlled by the queryInterval_ms setting, in milliseconds. Set it slightly longer than the interval between trigger events (for example, 101 ms for a 10 Hz trigger) and update it whenever the repetition rate changes.