Why are pulse repetition frequency (PRF) and duty cycle important?

The significance of pulse repetition frequency (PRF) and duty cycle in radar and lidar systems lies in their direct impact on system performance characteristics.

When it comes to PRF, it is crucial because it determines the maximum unambiguous range of the radar or lidar system. This is because the PRF establishes the time intervals at which pulses are transmitted. If the PRF is too low relative to the speed of the target, the system may not be able to distinguish between return signals from different pulses, leading to range ambiguities. Thus, a well-chosen PRF allows the system to effectively measure distances by ensuring that returning echoes are received before the next pulse is sent.

Duty cycle, defined as the ratio of the time the system is actively transmitting pulses to the total time period, affects system sensitivity and resolution. A higher duty cycle allows for more frequent pulse transmission, which can improve the signal-to-noise ratio and enhance the system's ability to detect weaker signals. This is critical in environments where targets may be difficult to identify due to interference or distance.

In essence, both PRF and duty cycle are fundamental parameters that influence how well a radar or lidar system can operate in various conditions, ultimately determining its effectiveness in target detection and imaging.