Receiving apparatus
A receiving apparatus includes: M receivers configured to receive signals based on sound waves propagating in water; M FIR filters configured to perform waveform operation on the signals received by the receivers; a combiner configured to combine output signals of the M FIR filters; and a filter coefficient calculation portion configured to calculate a tap coefficient of the M FIR filters so as to reduce an error of the output signals combined by the combiner. The M FIR filters have a tap length that is shorter than a delay spread that is a possible range between a time of arrival of a direct wave and a time of arrival of a delayed wave of the sound waves.
1. A receiving apparatus comprising:
M receivers configured to receive signals based on sound waves propagating in water;
M FIR filters configured to perform waveform operation on the signals received by the receivers;
a combiner configured to combine output signals of the M FIR filters; and
a filter coefficient calculator configured to calculate a tap coefficient of the M FIR filters so as to reduce an error of the output signals combined by the combiner,
wherein the M FIR filters have a tap length that is shorter than a delay spread that is a possible range between a time of arrival of a direct wave and a time of arrival of a delayed wave of the sound waves, where M is an integer greater than or equal to two.
2. The receiving apparatus according to claim 1 , wherein the tap length is longer than a time obtained by dividing a distance that is largest among distances between every pairs of the M receivers by a sound velocity in water, where M as it relates to M receivers is an integer greater than or equal to three.
3. The receiving apparatus according to claim 1 , wherein a value of M is a positive integer greater than a number of delayed waves to be processed.
4. The receiving apparatus according to claim 1 , further comprising M converters configured to convert the sound waves received by the receivers into digital signals.
5. The receiving apparatus according to claim 4 , wherein the converters are configured to further perform frequency conversion on signals of the sound waves.