RUNRACE : Service & Maintenance Manual - rev. 2.0
Page 11.2
There are 3 types of problems which can typically occur on the heart rate signal:
• interference caused by disturbances from sources of electromagnetic noise. These problems
cause the heart rate signal to deviate from the rear value, typically making it higher;
• saturation caused by disturbances from sources of electromagnetic noise. In this case the
receiver is no longer able to detect any heart rate signal;
• cross-talk similar to the interference problem, but is caused by reception of a signal from
another strap, typically worn by users on adjacent machines if they are too close together.
The following paragraphs contain various suggestions which may be useful for improving the
reception of the cardio signal.
11.1.1. TYPE OF ASIC
The cardio receivers can be equipped with 3 different types of ASIC models, identifiable by the
code marked on the component: MAS, FTC or HRRE. These ASICs are characterized by different
reception ranges and different levels of immunity to noise. Tests have determined that the maximum
reception distances are as follows:
ASIC DISTANCE
(cm)
MAS 90
FTC 100
HRRE 85
As regards sensitivity to noise, the best ASIC is the HRRE model. This ASIC is also the one
recommended by the manufacturer.
11.1.2. PRESENCE OF ELECTROMAGNETIC FIELDS
The receiver is sensitive to electromagnetic fields produced by the switching of LEDs, motor
brushes, the commutation of power devices, monitors, neon lights, stereo equipment, etc., which can
impair its operation. It has been found that such electromagnetic fields directly affect the analog part
