  We propose an objective measurement method for pitch extractors' responses to
frequency-modulated signals. The method simultaneously measures the linear and
the non-linear time-invariant responses and random and time-varying responses.
It uses extended time-stretched pulses combined by binary orthogonal sequences.
Our recent finding of involuntary voice pitch response to auditory stimulation
while voicing motivated this proposal. The involuntary voice pitch response
provides means to investigate voice chain subsystems individually and
objectively. This response analysis requires reliable and precise pitch
extraction. We found that existing pitch extractors failed to correctly analyze
signals used for auditory stimulation by using the proposed method. Therefore,
we propose two reference pitch extractors based on the instantaneous frequency
analysis and multi-resolution power spectrum analysis. The proposed extractors
correctly analyze the test signals. We open-sourced MATLAB codes to measure
pitch extractors and codes for conducting the voice pitch response experiment
on our GitHub repository.
