Receiver architectures for digital radio broadcasts and associated methods
View Patent ↗Receiver architectures and related methods are disclosed for high definition (HD) and digital radio FM broadcast receivers. The radio receiver architectures are configured to utilize multiple analog-to-digital converters (ADCs) to handle the digital radio spectrum and can be configured to modify a target IF frequencies depending upon the mode of operation of the receiver. For example, the receiver can include an analog FM reception mode and a digital FM reception mode for which different down-conversions are used for the same analog-plus-digital audio broadcast channel. If desired, the radio broadcast receivers disclosed can be configured so that they only receive digital FM radio content, for example, if the analog FM broadcast was of no interest and/or if the broadcast was all digital.
1. An integrated digital audio receiver, comprising:
mixing circuitry configured to mix radio frequency (RF) input signals with mixing signals to down convert audio broadcast channels within the RF signals to one or more target frequencies and to output analog real (I) and imaginary (Q) signals, the RF signals including one or more audio broadcast channels having digital audio signals;
local oscillator (LO) circuitry configured to provide the mixing signals to the mixing circuitry, the mixing signals being dependent upon an audio broadcast channel to be tuned;
first analog to digital conversion (ADC) circuitry coupled to receive the analog I/Q signals and to output a first set of digital I/Q signals;
second analog to digital conversion (ADC) circuitry coupled to receive the analog I/Q signals and to output a second set of digital I/Q signals; and
digital signal processing (DSP) circuitry configured to receive and digitally process the first set of digital I/Q signals, and to receive the second set of digital I/Q signals;
wherein the second ADC circuitry is configured to be turned off for at least one mode of operation.
2. The integrated digital audio receiver of claim 1 , wherein one or more audio broadcast channels have digital audio signals and analog audio signals.
3. The integrated digital audio receiver of claim 2 , wherein the analog audio signals are centered on a broadcast channel center frequency and wherein the digital audio signals are located in one or more sideband frequency ranges offset from the broadcast channel center frequency.
4. The integrated digital audio receiver claim 3 , further comprising control circuitry coupled to the LO circuitry, the first ADC circuitry, the second ADC circuitry and the DSP circuitry, and wherein the control circuitry is configured to provide for an analog reception mode of operation and a digital reception mode of operation.
5. The integrated digital audio receiver of claim 4 , wherein the mixing signals are selected to down convert the broadcast channel center frequency to an identical frequency in both the analog reception mode of operation and the digital reception mode of operation.
6. The integrated digital audio receiver of claim 4 , wherein the mixing signals are selected to down convert the broadcast channel center frequency to different frequencies in the analog reception mode of operation and the digital reception mode of operation.
7. The integrated digital audio receiver of claim 6 , wherein the mixing signals are selected to down convert the broadcast channel center frequency to a low intermediate frequency (low-IF) in the analog mode of operation and to zero-IF in the digital mode of operation.
8. The integrated digital audio receiver of claim 1 , wherein the first ADC circuitry is configured to digitize signals in a first set of frequencies in the audio broadcast channel to be tuned and the second ADC circuitry is configured to digitize signals in a second set of frequencies in the audio broadcast channel to be tuned.