System and method of demodulating audio signals

A method comprising:

• receiving a modulated signal at an input of a demodulator;
• determining a first noise estimate of the modulated signal via a tunable noise mixer;
• generating a first output indicating a first carrier noise estimate of the modulated signal at a primary carrier frequency;
• generating a second output indicating a second carrier noise estimate of the modulated signal at a secondary carrier frequency;
• generating a third output of the first noise estimate;
• generating a fourth output indicating when a forced mono state is determined;
• generating a fifth output indicating when a mute state is determined;
• generating a sixth output indicating when the primary carrier is below a primary carrier threshold;
• and
• generating a seventh output indicating when the secondary carrier is below a secondary carrier threshold.

A device comprising:

• a radio frequency front end coupled to a first input, wherein the radio frequency front end is adapted to receive a broadcast television signal and to apply a gain to the broadcast television signal to produce a modulated signal;
• and
• a demodulator coupled to the radio frequency front end for determining a first carrier noise estimate of the modulated signal,
• wherein the first carrier noise estimate is determined independent of the gain and independent of an indicator of signal quality of the broadcast television signal at the radio frequency front end.

A method comprising:

• sending, from a controller to an audio demodulator, a first signal to disable an audio output limiting function in the audio demodulator;
• receiving, at the controller, a first indication from the audio demodulator when a first carrier noise estimate of a modulated audio signal is below a threshold;
• receiving, at the controller, a second indication from the audio demodulator of the first carrier noise estimate;
• and
• selectively limiting the audio output based on the first indication and the second indication.

A method comprising:

• sending, from a controller to a noise mixer, a first signal to selectively tune the noise mixer to multiple frequencies in a frequency spectrum of a modulated signal;
• receiving, at the controller, an indication of signal energy from a demodulator at each of the multiple frequencies to which the noise mixer is selectively tuned;
• determining an indicator of spectral content of the modulated signal as a function of frequency based on the indication of signal energy;
• and
• selectively limiting an output based on the indicator of spectral content.