Audio processing circuit, audio unit, integrated circuit and method for blending

A radio receiver that comprises:

• a time-to-frequency domain circuit configured to convert a primary audio signal and a secondary audio signal, wherein the primary audio signal is FM radio and the secondary audio signal is digital radio, in a time-domain form and output frequency spectrum representations thereof;
• a cross-fade magnitude circuit configured to obtain a cross-faded magnitude spectrum representation from at least one of the frequency spectrum representations;
• a cross-fade phase circuit configured to obtain a separate cross-faded phase spectrum representation from at least one of the frequency spectrum representations, wherein a determination is made whether to apply equal or different magnitude and phase spectrum representation cross fade times;
• and
• a frequency-to-time domain circuit configured to receive the separate cross-faded magnitude and cross-faded phase spectrum representations and output a time domain signal.

An integrated circuit for a radio receiver that includes an audio processing circuit that comprises:

• a time-to-frequency domain circuit configured to convert a primary audio signal and a secondary audio signal, wherein the primary audio signal is FM radio and the secondary audio signal is digital radio, in a time-domain form and output frequency spectrum representations thereof;
• a cross-fade magnitude circuit configured to obtain a cross-faded magnitude spectrum representation from at least one of the frequency spectrum representations;
• a cross-fade phase circuit configured to obtain a separate cross-faded phase spectrum representation from at least one of the frequency spectrum representations, wherein a determination is made whether to apply equal or different magnitude and phase spectrum representation cross fade times;
• and
• a frequency-to-time domain circuit configured to receive the separate cross-faded magnitude and cross-faded phase spectrum representations and output a time domain signal.

A method of spectrum blending in a radio receiver, the method comprising:

• receiving, in the radio receiver, a primary audio signal and a secondary audio signal, wherein the primary audio signal is FM radio and the secondary audio signal is digital radio, in a time-domain form;
• converting, in the radio receiver, the primary audio signal and the secondary audio signal into frequency spectrum representations thereof;
• obtaining, in the radio receiver, a cross-faded magnitude spectrum representation and a separate cross-faded phase spectrum representation from at least one of the frequency spectrum representations;
• determining whether to apply equal or different magnitude and phase spectrum representation cross fade times;
• converting, in the radio receiver, the cross-faded magnitude spectrum representation and separate cross-faded phase spectrum representation into a time domain signal;
• and
• outputting, from the radio receiver, blended time-domain signals.