RUNRACE : Service & Maintenance Manual - rev. 2.0
Page 11.1
11. APPENDIX
11.1. TECHNICAL NOTES ON CARDIO RECEIVERS
Technogym utilizes Polar technology for measuring the heart rate frequency of the person training
on the machine. The Polar system consists of:
• a transmitter, worn by the person training on the machine, which uses 2 electrodes to detect the
electrical activity of the heart and transmits the measured heart rate by sending an
electromagnetic signal at a frequency of 5 kHz.
• a receiver, shown in the figure below, which consists of:
Figure 11.1-1
− an antenna a, designated the “coil”, which receives the signal from the transmitter strap
worn by the user.
− an integrated circuit b, designated the ASIC, which has the function of filtering the analog
signal and generating a pulse train corresponding to the received heart rate.
− two contacts c parallel to the coil, on which a 15 KOhm resistor is sometimes mounted.
The receiver is connected to the CPU board by means of 3 wires for:
− +5 Vdc power supply;
− Output signal (heart rate);
− ground.
The output is a digital signal that is normally at 5 Vdc and goes to 0 Vdc for a few msec when a
heart beat is detected, as shown in the figure below.
