# range2tl

Compute underwater sound transmission loss from range

## Syntax

``tl = range2tl(rng,freq,depth)``

## Description

example

````tl = range2tl(rng,freq,depth)` returns the transmission loss, `tl`, for a sound wave of frequency `freq` arriving from a source at distance `rng`. The channel depth is `depth`. The transmission loss is due to geometrical spreading and frequency-dependent absorption. This function is the inverse of `tl2range`.```

## Examples

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Find the transmission loss (in dB) for a sonar operating at 2 kHz in a channel that is 200 m deep. The sound path is 1000.0 m long.

```rng = 1000.0; freq = 2000.0; depth = 200; tl = range2tl(rng,freq,depth)```
```tl = 50.1261 ```

## Input Arguments

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Distance from sound source to receiver, specified as a positive scalar. Units are in meters.

Example: `10e3`

Data Types: `double`

Frequency of sound, specified as a positive scalar. Units are in Hz.

Example: `1e3`

Data Types: `double`

Channel depth, specified as a positive scalar. Units are in meters.

Example: `200`

Data Types: `double`

## Output Arguments

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Transmission loss, returned as a positive scalar. Units are in dB.

Data Types: `double`

## Limitations

• The transmission loss model assumes that seawater salinity is 35 ppt, pH is 8, and temperature is 10°C.

• The transmission loss model is valid for frequencies less than or equal to 2.0 MHz.

 Ainslie M. A. and J.G. McColm. "A simplified formula for viscous and chemical absorption in sea water." Journal of the Acoustical Society of America, Vol. 103, Number 3, 1998, pp. 1671--1672.

 Urick, Robert J. Principles of Underwater Sound, 3rd ed. Los Altos, CA:Peninsula Publishing, 1983.