Block: BandpassBiQ



PIC




Inports


In

Input In(k)






Outports


Out

Output Out(k)







Mask Parameters



Name

ID

Description




characteristic

1

The filter characteristic is one of Butterworth (=Bessel) or Chebyshev




fc1

2

Lower cut-off frequency in Hz




fc2

3

Upper cut-off frequency in Hz




rc

4

Attenuation at cut-off frequencies




ts_fact

5

Multiplication factor of base sampling time (in integer format)





Description:

Calculates the filter coefficients for a second order bandpass and performs filtering on input signal.

Second order transfer function used:

H(z) = (b0.z2 + b1.z + b2) / (z2 + a1.z + a2)

Butterworth

E.g.:
The cut-off frequencies are fc1 = 10Hz and fc2 = 100Hz.
The bodeplot is shown in the figure 1 below.


PIC

Figure 1: Bodeplot Butterworth bandpass.


Chebyshev
Note: A second order Chebyshev I bandpass has the same bodeplot as a second order Chebyshev II bandpass. Hence, only the ’Chebyshev’ option is given.

E.g.:
The cut-off frequencies are fc1 = 10Hz and fc2 = 100Hz.
The parameter rc is set to 10dB.
The bodeplot is shown in the figure 2 below.


PIC

Figure 2: Bodeplot Chebyshev bandpass. rc = 10dB


Bessel
Note: A second order Bessel bandpass behaves exactly like a second order Butterworth bandpass. Hence, no ’Bessel’ option is given.

Implementations:
FiP16 16 Bit Fixed Point Implementation
FiP32 32 Bit Fixed Point Implementation
Float32 32 Bit Floating Point Implementation
Float64 64 Bit Floating Point Implementation

Implementation: FiP16


16 Bit Fixed Point Implementation



Inports Data Type


In

int16






Outports Data Type


Out

int16




Implementation: FiP32


32 Bit Fixed Point Implementation



Inports Data Type


In

int32






Outports Data Type


Out

int32




Implementation: Float32


32 Bit Floating Point Implementation



Inports Data Type


In

float32






Outports Data Type


Out

float32




Implementation: Float64


64 Bit Floating Point Implementation



Inports Data Type


In

float64






Outports Data Type


Out

float64