Receiver chip with multiple independent loop-through paths

1. A radio receiver comprising:

a radio frequency (RF) receive path configured to convey a first radio signal within a first band to a radio tuning circuit, wherein the RF receive path is controllable using a first automatic gain control (AGC) circuit; and

a loop-through path configured to convey a second radio signal within a second band between an input and an output of the radio receiver, wherein the second band is different from the first band, and wherein the loop-through path is controllable using a second AGC control circuit.

2. The radio receiver as recited in claim 1 , wherein the loop-through path is further configured to convey a radio signal, within the first band, on the loop-through path.

3. The radio receiver as recited in claim 1 , further comprising a plurality of loop-through paths each having an input and an output, the plurality of loop-through paths including the loop-through path, wherein each of the loop-through paths provides a signal path between its respective input and respective output, and wherein a gain through each of the loop-through paths is separately controllable using AGC circuitry.

4. The radio receiver as recited in claim 3 , wherein each of the plurality of loop-through paths is configured to pass signals in a one of a plurality of different bands wherein the plurality of bands includes two or more of the following:

a frequency modulation (FM) band;

an amplitude modulation (AM) band;

digital audio broadcast (DAB) L-band; and

DAB band III.

5. The radio receiver as recited in claim 3 , wherein the tuning path RF receive path is coupled to one of the plurality of loop-through paths, and wherein the radio receiver further comprises a selection circuit having a plurality of inputs each coupled to a corresponding one of the plurality of plurality of loop-through paths and an output coupled to the radio tuning circuit, wherein the selection circuit is configured to couple a selected one of the plurality of loop-through paths to the radio tuning circuit.

6. The radio receiver as recited in claim 1 , wherein the radio receiver is configured to convey a radio signal in the amplitude modulated (AM) band on the loop-through path.

7. The radio receiver as recited in claim 1 , wherein the radio tuning circuit includes:

a local oscillator configured to generate a periodic signal, wherein the periodic signal has a selectable frequency;

a mixer coupled to receive the periodic signal and further configured to receive the first signal, wherein the mixer is configured to down-convert the first radio signal to an intermediate frequency (IF) signal.

8. The radio receiver as recited in claim 1 , wherein power for each of the tuning and loop-through paths are each separately controllable from one another.

9. A method comprising:

conveying a first radio signal in a first band to a radio tuning circuit via a radio frequency (RF) receive path of a radio receiver;

controlling a gain of the first radio signal using first automatic gain control (AGC) circuitry;

conveying a second radio signal in a second band on a loop-through path between an input and an output of the radio receiver, wherein the second band is different from the first band; and

controlling a gain of the second radio signal using second AGC circuitry.

10. The method as recited in claim 9 , further comprising conveying the second radio signal in the first band on the loop-through path.

11. The method as recited in claim 9 , further comprising:

conveying radio signals through two or more of a plurality of loop-through paths each having an input, an output, and corresponding AGC circuitry;

controlling a gain in at least one of the plurality of loop-through paths, using its AGC circuitry, separate from the other ones of the plurality of loop-through paths.

12. The method as recited in claim 9 , wherein the first band and the second band are selected from the following bands:

a frequency modulation (FM) band;

an amplitude modulation (AM) band;

digital audio broadcast (DAB) L-band; and

DAB band III.

13. The method as recited in claim 9 , wherein the second band is an amplitude modulated (AM) band on the loop-through path.

14. A radio receiver comprising:

a radio receiver integrated circuit including a plurality of loop-through paths each having an input and an output, wherein each of the loop-through paths provides a signal path between its respective input and respective output, and wherein a gain through each of the loop-through paths is separately controllable using automatic gain control (AGC).

15. The radio receiver as recited in claim 14 , wherein each of the plurality of loop-through paths includes a corresponding low noise amplifier (LNA), wherein the LNA of each of the plurality of loop-through paths includes an input coupled to the input of its corresponding loop-through path.

16. The radio receiver as recited in claim 15 , wherein each of the plurality of loop-through paths includes a corresponding buffer circuit having input coupled to an output of the corresponding LNA of that loop-through path and an output coupled to the output of its corresponding loop-through path.

17. The radio receiver as recited in claim 14 , wherein each of the plurality of loop-through paths is configured to pass signals in a unique one of a plurality of frequency bands.

18. The radio receiver as recited in claim 17 , wherein the plurality of bands includes two or more of the following:

a frequency modulation (FM) band;

an amplitude modulation (AM) band;

digital audio broadcast (DAB) L-band;

DAB band III.

19. The radio receiver as recited in claim 14 , wherein power for each of the plurality of loop-through paths is separately controllable.

20. The radio receiver as recited in claim 14 , wherein the plurality of loop-through paths is implemented on a single integrated circuit.