Input/Output Wave From (Reference): VSS

WARNING: This page is about a different car, the 2009 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.

TCM terminals
2P (+)-body GND (-)
Oscilloscope setting
1 V/DIV (Y), 2.5 ms/DIV (X), DC range
Test Condition
Vehicle speed at 30 km/h {19 mph}.

Fig 1: Waveform Graph - VSS
Courtesy of MAZDA MOTORS CORP.