FM demodulator having DC offset compensation

A frequency modulated signal demodulator including a DC offset compensation circuit, wherein the DC offset compensation circuit comprising;

• means for deriving the positive and negative peak values of a frequency demodulated signal;
• means for determining the mean of the positive and negative peak values as an estimate of a DC offset value;
• and,
• means for utilising this estimated DC offset value to compensate for DC offset in the frequency demodulated signal;
• an input for receiving a frequency demodulated signal;
• an output for an estimated DC offset signal;
• a first diode having its cathode connected to the input and its anode connected to a ground terminal via a first capacitor, wherein the anode is also connected to a negative supply terminal via a first resistor and to the output via a second resistor;
• a second diode having its anode connected to the input and its cathode connected to a ground terminal via a second capacitor, wherein the cathode is also connected to a positive supply terminal via a third resistor and to the output via a fourth resistor;
• and
• an output capacitor connected between the output and a ground terminal.

A frequency modulated signal demodulator including a DC offset compensation circuit, wherein the DC offset compensation circuit comprises:

• means for deriving the positive and negative peak values of a frequency demodulated signal;
• means for determining the mean of the positive and negative peak values as an estimate of a DC offset value;
• and,
• means for utilising this estimated DC offset value to compensate for DC offset in the frequency demodulated;
• signal strength switching means for disconnecting the frequency demodulated signal from the input of the DC offset compensation circuit during weak-signal conditions.

A frequency modulated signal demodulator including a DC offset compensation circuit, wherein the DC offset compensation circuit comprises;

• means for deriving the positive and negative peak values of a frequency demodulated signal;
• means for determining the mean of the positive and negative peak values as an estimate of a DC offset value;
• and,
• means for utilising this estimated DC offset value to compensate for DC offset in the frequency demodulated;
• signal strength switching means for disconnecting an output capacitor from the DC offset compensation circuit during weak-signal conditions.

A frequency modulated signal demodulator including a DC offset compensation circuit, wherein the DC offset compensation circuit comprises:

• means for deriving the positive and negative peak values of a frequency demodulated signal;
• means for determining the mean of the positive and negative peak values as an estimate of a DC offset value;
• and,
• means for utilising this estimated DC offset value to compensate for DC offset in the frequency demodulated signal;
• comprising signal strength switching means for disconnecting the frequency demodulated signal from the input to the DC offset compensation circuit and for disconnecting an output capacitor from the DC offset compensation circuit during weak-signal conditions.