Abstract: A pulse responsive device, for example, a pulse rate meter or pulse oximetry device, is disclosed, which includes a light emitter and a light sensor for receiving light from the emitter after transmission through, or reflection from, body tissue to give an electrical signal varying according to blood flow or other fluid pulsations. A movement transducer gives an additional electrical signal representing body movements or vibrations, but independent of blood flow pulsations. This movement transducer may include a light emitter and sensor responsive to a different wavelength from the light emitter and light sensor used for measuring, and varying with, blood flow or other fluid pulsations. The pulse responsive device compares the two electrical signals produced to cancel out the movement or vibration noise fro the signal obtained from the light sensor which obtains measurements which vary with blood or other fluid flow pulsations.