# Linear Chirp Specifications

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The following specifications apply to the Configure Chirp (N Ch) VI when configuring a linear chirp signal.

 Start frequency range 0 to PDM rate/2 Stop frequency range 0 to PDM rate/2 Pre-chirp duration range 0 to 232 − 1 PDM samples, or approximately 23 minutes at PDM rate of 3.072 MHz Chirp duration range 0 to 232 − 1 − Pre-chirp duration samples

The linear chirp rate range, in seconds, is defined by the following equation:

$\text{Linear chirp rate range}=\text{}±\left(\text{Stop freq - Start freq}\right)/\text{Chirp duration}$

Refer to the following table for maximum chirp rates at different PDM rates.

Table 1. Maximum Linear Chirp Rate at Different PDM Rates
Maximum Linear Chirp Rate PDM Rate = 600 kHz PDM Rate = 800 kHz PDM Rate = 2.4 MHz PDM Rate = 3.072 MHz PDM Rate = 4.8 MHz
Range ±1.37 MHz/s ±2.44 MHz/s ±21.9 MHz/s ±35.9 MHz/s ±87.8 MHz/s
Minimum Time DC to PDM rate/2 7 ms 5 ms 2 ms 2 ms 1 ms