Abstract: An analog signal analyzer is described for counting the number of significant peaks and valleys in an analog signal. The analyzer includes an analog-to-digital converter, a signal-amplitude change-detector, a presettable counter presettable by a threshold-rate-factor number "n", and a logic circuit which detects a reversal in the direction of the signal-amplitude-changes between successive sampling times, and down-counts the counter each sample time in which the signal-amplitude changes continue in the same direction until "n+1" counts are reached. At that time it produces an output count, reloads the counter with the number "n", and conditions the circuit for thereafter down-counting the counter only when the signal-amplitude-change is in the reverse direction.

Abstract: A method and apparatus for measuring sperm motility are described in which a suspension of the sperm cells is placed in a transparent container, and a predetermined field of the specimen is continuously examined by photoelectric means for detecting variations in optical density caused by the collective wave-like motion of batches of the sperm cells through the examined field. An amplitude-modulated analog electrical signal is generated by the photoelectric means in response to the variations in optical density, and the peaks and valleys of this signal are counted over a predetermined time period to provide an index of sperm motility. This technique may be, and preferably is, performed on undiluted sperm suspensions as taken from the sperm-producing organism. In addition, it may be performed quickly, is non-destructive, and provides an objective index of motility which has been found to closely correlate with actual results.