Amplification circuit

An amplification circuit comprising:

• a first surface acoustic wave (SAW) filter comprising:
• an input for receiving an input signal;
• a first differential output;
• and
• a second differential output;
• wherein the first filter has a differential mode of operation for frequencies in its pass-band and a common mode of operation for frequencies outside its pass-band;
• and further having:
• a first magnitude transfer function from the input of the first filter to the first differential output of the first filter;
• a second magnitude transfer function from the input of the first filter to the second differential output of the first filter;
• a first phase transfer function from the input of the first filter to the first differential output of the first filter;
• and
• a second phase transfer function from the input of the first filter to the second differential output of the first filter;
• and wherein
• the difference between the first magnitude transfer function and the second magnitude transfer function for frequencies outside the pass-band of the first filter is less than a first threshold value of 3 dB;
• the difference between the first phase transfer function and the second phase transfer function for frequencies outside the pass-band of the first filter is less than a second threshold value of 40°;
• the difference between the first phase transfer function and the second phase transfer function for frequencies inside the pass-band of the first filter is less than a third threshold value of 20° away from 180°
• an LNA comprising:
• a first differential input connected to the first differential output of the first filter;
• a second differential input connected to the second differential output of the first filter;
• and
• an output for providing an amplified output signal.