Digital multiband filter and method thereof

A digital filter, comprising:

• a multiband filter having an input receiving a digital input signal and having an output for providing an output signal having a low-pass response at a first predetermined frequency and a band-pass response between second and third predetermined frequencies;
• a notch filter having an input receiving said output signal of said multiband filter for rejecting said band-pass response while passing said low-pass response at said first predetermined frequency to an output;
• a first delay circuit having an input coupled to said output of said multiband filter for providing a delayed multiband signal at an output;
• and
• a junction circuit having first and second inputs and an output, said first input being coupled to said output of said delay circuit, said second input being coupled to said output of said notch filter, said output providing said band-pass response isolated from said low-pass response by subtracting said low-pass response provided by said notch filter from said delayed multiband signal.

A method of filtering a digital input signal, comprising the steps of:

• filtering the digital input signal for providing a multiband output signal having a low-pass response at a first predetermined frequency and a band-pass response between second and third predetermined frequencies;
• filtering said multiband output signal to reject said band-pass response while passing said low-pass response at said first predetermined frequency;
• delaying said multiband output signal for providing a delayed multiband signal;
• and
• subtracting said low-pass response from said delayed multiband signal for providing said band-pass response isolated from said low-pass response.

A digital filter, comprising:

• a multiband filter having an input receiving a digital input signal and having an output for providing an output signal having a low-pass response at a first predetermined frequency and a band-pass response between second and third predetermined frequencies;
• a band-pass filter having an input receiving said output signal of said multiband filter for rejecting said low-pass response at said first predetermined frequency while passing said band-pass response to an output;
• a first delay circuit having an input coupled to said output of said multiband filter for providing a delayed multiband signal at an output;
• and
• circuit means coupled for subtracting said band-pass response provided by said band-pass filter from said delayed multiband signal to isolate said low-pass response.