Method and apparatus for sensing inter-modulation to improve radio performance in single and dual tuner

Patent metadata

Field	Value
Publication number	US-9838053-B2
Application number	US-201615286073-A
Country	US
Kind code	B2
Filing date	Oct 5, 2016
Priority date	Jan 20, 2011
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

A method of performing alternate frequency switching in a radio includes tuning the radio to a primary frequency. A candidate alternate frequency is identified. It is determined whether the candidate alternate frequency is a third order inter-modulation artifact. Tuning is switched from the primary frequency to the candidate alternate frequency only if it is determined in the determining step that the candidate alternate frequency is not a third order inter-modulation artifact.

First claim

What is claimed is:

1. A radio comprising:
a tuner configured to tune to a primary frequency; and
a controller configured to:
determine whether a candidate alternate frequency is a third order inter-modulation artifact; and
cause the tuner to switch tuning from the primary frequency to the candidate alternate frequency only if it is determined that the candidate alternate frequency is not a third order inter-modulation artifact.

2. The radio of claim 1 wherein the controller is configured to ascertain whether content of the candidate alternate frequency is equivalent to content of the primary frequency, the ascertaining being performed only if it is determined that the candidate alternate frequency is not a third order inter-modulation artifact, the controller being configured to cause the tuner to switch tuning from the primary frequency to the candidate alternate frequency only if it is ascertained that the content of the candidate alternate frequency is equivalent to the content of the primary frequency.

3. The radio of claim 2 wherein the ascertaining and the switching are performed during a pause in a currently tuned-to frequency.

4. The radio of claim 2 wherein the ascertaining is performed only if it is determined that a signal quality of the candidate alternate frequency exceeds a threshold signal quality level.

5. The radio of claim 1 wherein the controller is configured to perform a program identification check for the candidate alternate frequency only if it is determined that the candidate alternate frequency is not a third order inter-modulation artifact.

6. The radio of claim 1 wherein the controller is configured to identify two frequencies f 1 and f 2 within an FM band that have a signal quality above a threshold level, the determining including determining whether the candidate alternate frequency equals either:
L*f1+M*f2; or
L*f1−M*f2

wherein L and M are integers and L+M=3.

7. The radio of claim 1 wherein the controller is configured to identify three frequencies f 1 , f 2 and f 3 within an FM band that have a signal quality above a threshold level, the determining including determining whether the candidate alternate frequency equals either:
L*f1+M*f2+N*f3;
L*f1+M*f2−N*f3;

L*f1−M*f2+N*f3; or

L*f1−M*f2−N*f3

wherein L, M and N are integers and L+M+N=3.

8. The radio of claim 1 wherein the controller is configured to cause the tuner to tune to the candidate alternate frequency in an autoseek operation only if it is determined that the candidate frequency is not a third order inter-modulation artifact.

9. The radio of claim 1 wherein the controller is configured to cause the tuner to switch tuning from the primary frequency to the candidate alternate frequency only if it is ascertained that a signal quality of the candidate alternate frequency is better than a signal quality of the primary frequency.

10. A radio comprising:
a tuner configured to scan a radio frequency band for a candidate frequency having a quality exceeding a threshold quality level; and
a controller coupled to the tuner and configured to:
determine whether the candidate frequency is a third order inter-modulation artifact; and
cause the tuner to tune to the candidate frequency only if it is determined that the candidate frequency is not a third order inter-modulation artifact.

11. The radio of claim 10 wherein the controller is configured to cause the tuner to switch tuning from a primary frequency to the candidate frequency in an alternate frequency switching operation only if it is determined that the candidate frequency is not a third order inter-modulation artifact.

12. The radio of claim 10 wherein the scanning includes scanning the radio frequency band for a candidate frequency having a signal quality metric exceeding a threshold signal quality metric, the signal quality metric being dependent upon at least one of field strength, multipath, adjacent channel energy, frequency offset and FM modulation.

13. The radio of claim 10 wherein the controller is configured to identify two frequencies f 1 and f 2 within an FM band that have a signal quality above a threshold level, the determining including determining whether the candidate frequency equals either:
L*f1+M*f2; or
L*f1−M*f2

wherein L and M are integers and L+M=3.

14. The radio of claim 10 wherein the controller is configured to identify three frequencies f 1 , f 2 and f 3 within an FM band that have a signal quality above a threshold level, the determining including determining whether the candidate frequency equals either:
L*f1+M*f2+N*f3;
L*f1+M*f2−N*f3;

L*f1−M*f2+N*f3; or

L*f1−M*f2−N*f3

wherein L, M and N are integers and L+M+N=3.

15. A radio comprising:
a tuner; and
a controller configured to:
identify a first frequency within an FM band that has a signal quality above a threshold level;
calculate a second frequency that is a third order inter-modulation artifact of the first frequency; and
inhibit the tuner from tuning to the second frequency.

16. The radio of claim 15 wherein the inhibiting is performed in an alternative frequency switching operation.

17. The radio of claim 15 wherein the inhibiting is performed in an autoseek operation.

18. The radio of claim 15 wherein the controller is configured to determine the signal quality of the first frequency by measuring field strength, multipath, adjacent channel energy, frequency offset and/or FM modulation of the first frequency.

19. The radio of claim 15 wherein the controller is configured to identify a plurality of first frequencies within an FM band that have a signal quality above a threshold level, the calculating includes calculating, for two said first frequencies f 1 and f 2 :
L*f1+M*f2; and
L*f1−M*f2

for each combination of L and M wherein L and M are integers and L+M=3.

20. The radio of claim 15 wherein the controller is configured to identify a plurality of first frequencies within an FM band that have a signal quality above a threshold level, the calculating includes calculating, for three said first frequencies f 1 , f 2 and f 3 :
L*f1+M*f2+N*f3;
L*f1+M*f2−N*f3;

L*f1−M*f2+N*f3; and

L*f1−M*f2−N*f3

for each combination of L, M and N wherein L, M and N are integers and L+M+N=3.

Assignees

• Panasonic Automotive Systems Co America Div Panasonic Corp North America

Inventors

• Thomas Donald
• Hingerton Jason
• Fujisawa Tatsuya
• Chu Jammie
• Jaisimha Shree
• Baillargeon Robert

Classifications

• H04L25/08

  Modifications for reducing interference; Modifications for reducing effects due to line faults {; Receiver end arrangements for detecting or overcoming line faults} · CPC title

• H04W52/0209

  in terminal devices · CPC title

• H04B2001/1072

  by tuning the receiver frequency · CPC title

• H04B17/345

  Interference values ({signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR]} H04B17/336) · CPC title

• H04B1/082

  to be used in vehicles (H04B1/086 takes precedence; holding or mounting accessories B60R11/02) · CPC title