What is a heartbeat in telemetry systems?

• A. A small regular signal indicating the system is alive.
• B. A continuous high-rate stream of sensor data.
• C. A method to encrypt telemetry packets.
• D. A process to reset the system automatically.

Answer: (A)

A heartbeat is a lightweight, periodic signal used in telemetry to show that a node or link is alive and reachable. It is kept deliberately small and quick, just enough to confirm connectivity and timing, not to carry the main sensor data. Regular heartbeats let the system detect when a component fails or a connection drops, so timeouts and alerts can be triggered promptly. This is different from a continuous high-rate stream of data, which is the actual measurements; it is not a method to encrypt packets; and it is not a automatic reset process. So the best description is a small regular signal indicating the system is alive.