How to use Arduino as an emulator to filter signals ?

Arduino Code:

define<IIRFilter.h>
const double numerator={100, 68};
const double denominator={-98,7};
IIRFilter iir(numerator,denominator);
void setup()
{
    Serial.begin(9600);
}
void loop()
{
if(Serial.available()>0)
{
int u=Serial.read();
int filtered=iir.filter(u);
Serial.println(filtered)
}
}

[SOUMYA SUVRA GHOSAL]

The attachment is the Simulink model. But on scope no output is coming where using same filter coefficents the digital filter is working good.