Digital filter and its designing method

A digital filter, comprising a tapped delay line made up of a plurality of delay units, the digital filter multiplying signals of taps by given filter factors and then performing addition and output,

• the filter factors have a symmetrical sequence and values are set so that a sum of the sequence is zero and a sum of every other terms is equal to a sum of the other every other terms with opposite signs.

A digital filter, comprising a tapped delay line made up of a plurality of delay units, the digital filter multiplying signals of taps by given filter factors and then performing addition and output,

• the filter is designed based on first filter factors having a symmetrical sequence in which values are set so that a sum is not zero and a sum of every other terms is equal to a sum of the other every other terms with the same signs, and second filter factors are provided as filter factors for the signals of the taps, the second filter factors being obtained by reversing signs of values other than a median of the sequence of the first filter factors while causing absolute values of the sequence to remain the same.

A digital filter, comprising a tapped delay line made up of a plurality of delay units, the digital filter multiplying signals of taps by given filter factors and then performing addition and output,

• the filter is designed based on first filter factors having a symmetrical sequence in which values are set so that a sum is not zero and a sum of every other terms is equal to a sum of the other every other terms with the same signs, and second filter factors are provided as filter factors for the signals of the taps, the second filter factors being obtained by reversing signs of values other than a median of the sequence of the first filter factors while absolute values of the sequence is caused to remain the same, and subtracting the median of the sequence from a reference value.

A digital filter, comprising a tapped delay line made up of a plurality of delay units, the digital filter multiplying signals of taps by given filter factors and then performing addition and output,

• the filter is designed based on first filter factors having a symmetrical sequence in which values are set so that a sum is not zero and a sum of every other terms is equal to a sum of the other every other terms with the same signs, and second filter factors are provided as filter factors for the signals of the taps, the second filter factors having a sequence in which values are set so that sums of the first filter factors and the second filter factors serve as reference values.

A digital filter, comprising a tapped delay line made up of a plurality of delay units, the digital filter multiplying signals of taps by given filter factors and then performing addition and output,

• the filter is designed based on second filter factors having a symmetrical sequence in which values are set so that a sum is zero and a sum of every other terms is equal to a sum of the other every other terms with opposite signs, and first filter factors are provided as filter factors for the signals of the taps, the first filter factors being obtained by reversing signs of values other than a median of the sequence of the second filter factors while causing absolute values of the sequence to remain the same.

A digital filter, comprising a tapped delay line made up of a plurality of delay units, the digital filter multiplying signals of taps by given filter factors and then performing addition and output,

• the filter is designed based on second filter factors having a symmetrical sequence in which values are set so that a sum is zero and a sum of every other terms is equal to a sum of the other every other terms with opposite signs, and first filter factors are provided as filter factors for the signals of the taps, the first filter factors being obtained by reversing signs of values other than a median of the sequence of the second filter factors while causing absolute values of the sequence to remain the same, and subtracting the median of the sequence from a reference value.

A digital filter, comprising a tapped delay line made up of a plurality of delay units, the digital filter multiplying signals of taps by given filter factors and then performing addition and output,

• the filter is designed based on second filter factors having a symmetrical sequence in which values are set so that a sum is zero and a sum of every other terms is equal to a sum of the other every other terms with opposite signs, and first filter factors are provided as filter factors for the signals of the taps, the first filter factors having a sequence in which values are set so that sums of the first filter factors and the second filter factors serve as reference values.

A digital filter, comprising a tapped delay line made up of a plurality of delay units, the digital filter multiplying signals of taps by given filter factors and then performing addition and output,

• the filter is designed based on first filter factors having a symmetrical sequence in which values are set so that a sum is not zero and a sum of every other terms is equal to a sum of the other every other terms with the same signs, and second filter factors are provided as filter factors for the signals of the taps, the second filter factors being obtained by converting the sequence of the first filter factors and setting values so that a sum of the converted sequence is zero and a sum of every other terms is equal to a sum of the other every other terms with opposite signs in the converted sequence.

A digital filter comprising a tapped delay line made up of a plurality of delay units, the digital filter multiplying signals of taps by given filter factors and then performing addition and output,

• the filter is designed based on second filter factors having a symmetrical sequence in which values are set so that a sum is zero and a sum of every other terms is equal to a sum of the other every other terms with opposite signs, and first filter factors are provided as filter factors for the signals of the taps, the first filter factors being obtained by converting the sequence of the second filter factors and setting values so that a sum of the converted sequence is not zero and a sum of every other terms is equal to a sum of the other every other terms with the same signs in the converted sequence.

A method of designing a digital filter, the digital filter comprising a tapped delay line made up of a plurality of delay units, the digital filter multiplying signals of taps by given filter factors and then performing addition and output, the method comprises:

• determining filter factors for the signals of the taps by reversing signs of values other than a median of the sequence of basic filter factors while causing absolute values of the sequence to remain the same based on the basic filter factors having a symmetrical sequence in which values are set so that a sum is not zero and a sum of every other terms is equal to a sum of the other every other terms with the same signs.

A method of designing a digital filter, the digital filter comprising a tapped delay line made up of a plurality of delay units, the digital filter multiplying signals of taps by given filter factors and then performing addition and output, the method comprises:

• determining filter factors for the signals of the taps by reversing signs of values other than a median of the sequence of basic filter factors while causing absolute values of the sequence to remain the same, and subtracting the median of the sequence from a reference value, based on the basic filter factors having a symmetrical sequence in which values are set so that a sum is not zero and a sum of every other terms is equal to a sum of the other every other terms with the same signs.

A method of designing a digital filter, the digital filter comprising a tapped delay line made up of a plurality of delay units, the digital filter multiplying signals of taps by given filter factors and then performing addition and output, the method comprises:

• determining filter factors for the signals of the taps by reversing signs of values other than a median of the sequence of basic filter factors while causing absolute values of the sequence to remain the same based on the basic filter factors having a symmetrical sequence in which values are set so that a sum is zero and a sum of every other terms is equal to a sum of the other every other terms with opposite signs.

A method of designing a digital filter, the digital filter comprising a tapped delay line made up of a plurality of delay units, the digital filter multiplying signals of taps by given filter factors and then performing addition and output, the method comprises:

• determining filter factors for the signals of the taps by reversing signs of values other than a median of a sequence of basic filter factors while causing absolute values of the sequence to remain the same, and subtracting the median of the sequence from a reference value, based on the basic filter factors having a symmetrical sequence in which values are set so that a sum is zero and a sum of every other terms is equal to a sum of the other every other terms with opposite signs.

A method of designing a digital filter, the digital filter comprising a tapped delay line made up of a plurality of delay units, the digital filter multiplying signals of taps by given filter factors and then performing addition and output, the method comprises:

• determining filter factors for the signals of the taps by converting the sequence of basic filter factors and setting values so that a sum of the converted sequence is zero and a sum of every other terms is equal to a sum of the other every other terms with opposite signs in the converted sequence, based on the basic filter factors having a symmetrical sequence in which values are set so that a sum is not zero and a sum of every other terms is equal to a sum of the other every other terms with the same signs.

A method of designing a digital filter, the digital filter comprising a tapped delay line made up of a plurality of delay units, the digital filter multiplying signals of taps by given filter factors and then performing addition and output, the method comprises:

• determining filter factors for the signals of the taps by converting the sequence of basic filter factors and setting values so that a sum of the converted sequence is not zero and a sum of every other terms is equal to a sum of the other every other terms with the same signs in the converted sequence, based on the basic filter factors having a symmetrical sequence in which values are set so that a sum is zero and a sum of every other terms is equal to a sum of the other every other terms with opposite signs.

A method of designing a digital filter, the digital filter comprising a tapped delay line made up of a plurality of delay units, the digital filter multiplying signals of taps by given filter factors and then performing addition and output, the method comprises:

• cascading a basic filter inn stages (n=1), the basic filter being constituted using basic filter factors having a symmetrical sequence in which values are set so that a sum is not zero and a sum of every other terms is equal to a sum of the other every other terms with the same signs, and determining, as filter factors for the signals of the taps, nth-order filter factors obtained thus.

A method of designing a digital filter, the digital filter comprising a tapped delay line made up of a plurality of delay units, the digital filter multiplying signals of taps by given filter factors and then performing addition and output, the method comprises:

• cascading a basic filter inn stages (n=1), the basic filter being constituted using basic filter factors having a symmetrical sequence in which values are set so that a sum is zero and a sum of every other terms is equal to a sum of the other every other terms with opposite signs, and determining, as filter factors for the signals of the taps, nth-order filter factors obtained thus.

A method of designing a digital filter, the digital filter comprising a tapped delay line made up of a plurality of delay units, the digital filter multiplying signals of taps by given filter factors and then performing addition and output, the method comprises:

• shifting a pass frequency band of the filter by changing a delay rate of the delay unit in a basic filter constituted using basic filter factors having a symmetrical sequence in which values are set so that a sum is not zero and a sum of every other terms is equal to a sum of the other every other terms with the same signs.

A method of designing a digital filter, the digital filter comprising a tapped delay line made up of a plurality of delay units, the digital filter multiplying signals of taps by given filter factors and then performing addition and output, the method comprises:

• shifting a pass frequency band of the filter by changing a delay rate of the delay unit in a basic filter constituted using basic filter factors having a symmetrical sequence in which values are set so that a sum is zero and a sum of every other terms is equal to a sum of the other every other terms with opposite signs.