Particle analyzers and related methods for verifying the calibration status of a particle analyzer are provided. The particle analyzer includes independent of the presence or absence of particles. The methods and the analyzers include the use of different and non-interfering time-frequency domains,namely an intermediate frequency time domain and a low frequency time domain, and optionally a high frequency time domain. The high frequency time domain produces the laser facet drive current frequency modulation to prevent laser facet spatial mode hopping. The intermediate frequency time domain is used for particle detection. The low frequency time domain is used to calibrate states, including laser-pulse-light self-diagnostics, and is used for health or calibration states of the analyzer. By carefully selecting the frequency time domain range, interference does not exist, and the particle analyzer has the capacity of a self-diagnosis instrument irrelevant to particles.
Calibration verification of optical particle analyzers