Humminbird 1197C SI - Manual (Page 10)

The sound pulses are transmitted at various frequencies depending on
the application. Very high frequencies (455 kHz) are used for greatest
definition but the operating depth is limited. High frequencies (200 kHz)
are commonly used on consumer sonar and provide a good balance
between depth performance and resolution. Low frequencies (83 kHz) are
typically used to achieve greater depth capability.
The power output is the amount of energy generated by the sonar
transmitter. It is commonly measured using two methods:
• Root Mean Square (RMS) measures power output over the entire
transmit cycle.
• Peak to Peak measures power output at the highest points.
The benefits of increased power output are the ability to detect smaller
targets at greater distances, ability to overcome noise, better high speed
performance and enhanced depth capability.
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