sdr.fspl(d: ArrayLike, f: ArrayLike) → ndarray

Calculates the free-space path loss (FSPL) in dB.

\[\text{FSPL} = 10 \log_{10} \left( \frac{4 \pi d f}{c} \right)^2\]

Parameters:
d: ArrayLike

The distance \(d\) in meters between the transmitter and receiver.

f: ArrayLike

The frequency \(f\) in Hz of the signal.

Returns:

The free-space path loss (FSPL) in dB.

Examples

Compute the free-space path loss for a 1 km link at 1 GHz.

In [1]: sdr.fspl(1e3, 1e9)
Out[1]: 92.44778322188337

The free-space path loss is proportional to the square of the distance. So, doubling the distance results in a 6 dB increase in the free-space path loss.

In [2]: sdr.fspl(2e3, 1e9)
Out[2]: 98.468383135163

The free-space path loss is also proportional to the square of the frequency. So, doubling the frequency results in a 6 dB increase in the free-space path loss.

In [3]: sdr.fspl(1e3, 2e9)
Out[3]: 98.468383135163