If you are using one of our Animal Oximeter Pods to measure from an animal with heart rate at or below 450 BPM, you can view a pulse signal rather than the SpO2 reading by accessing the Oximeter Pod dialog from your channel menu dropdown, and selecting "Pulse." You can't view both at the same time though.
More details regarding the Animal Oximeter Pod can be found in the ML325 Data Card linked HERE.
If you are using the Oximeter Pod intended for human subjects, you can view a pulse signal by connecting a Pulse Transducer to another PowerLab input. More information about the Oximeter Pod can be found in the ML320 Data Card linked HERE.
For further technical assistance with this or any other issue, please contact ADInstruments Technical Support by clicking HERE.