Method and apparatus for backup power in a communication system
A digital receiver unit ( 28 ) having a backup energy source ( 214 ) for use in a vehicle ( 250 ) that operates on a primary energy source ( 216 ) includes a receiver ( 203 ) powered by the primary energy source when the vehicle is operating, a switching mechanism ( 210 and 212 ) for switching the receiver between the primary energy source and the backup energy source and a controller ( 210 ) coupled to the receiver for controlling the switching mechanism. The receiver receives data during a scheduled predetermined time and the backup energy source powers the receiver during the scheduled predetermined time if the vehicle is not operating.
1. A method for providing a backup energy source for a digital receiver in a vehicle, comprising the steps of:
powering the digital receiver with a primary energy source that powers the vehicle when the vehicle is operating;
storing a schedule of program content enabling a user of the digital receiver to selectively download at least a portion of said program content during a predetermined time; and
powering the digital receiver with the backup energy source during at least a portion of the predetermined time to enable the receipt of at least the portion of said program content selected when an ignition of the vehicle is disabled.
2. The method of claim 1 , wherein the method further comprises the step of recharging the backup energy source with the primary energy source when the vehicle is powered by the primary energy source.
3. The method of claim 1 , wherein the method further comprises the step of powering the digital receiver with the primary energy source when the vehicle is powered by the primary energy source.
4. The method of claim 1 , wherein the step of powering the digital receiver further comprises enabling the over-the-air receipt of all of the program content when the ignition of the vehicle is disabled.
5. The method of claim 1 , wherein the vehicle is operating when an ignition of the vehicle is enabled.
6. A digital receiver unit having a backup energy source for use in a vehicle that operates on a primary energy source, comprising:
a receiver powered by the primary energy source when the vehicle is operating, wherein the receiver receives data during a predetermined time;
a switching mechanism for switching the receiver between the primary energy source and the backup energy source; and
a controller coupled to the receiver for controlling the switching mechanism, wherein the backup energy source powers the receiver during at least a portion of the predetermined time if an ignition of the vehicle is disabled.
7. The digital receiver unit of claim 6 , wherein the unit further comprises a charging circuit coupled to the backup energy source and the primary energy source, enabling the primary energy source to recharge the backup energy source when the vehicle is operating.
8. The digital receiver unit of claim 6 , wherein the backup energy source and the primary energy source are batteries.
9. The digital receiver unit of claim 6 , wherein the receiver is a satellite digital audio receiver that receives a schedule of program content that enables a user to selectively download at least a portion of said program content during the predetermined time using the primary energy source when the vehicle is operating and using the backup energy source when the ignition of the vehicle is disabled.
10. The digital receiver unit of claim 6 , wherein the data comprises program content.
11. The digital receiver unit of claim 6 , wherein the vehicle is operating when the ignition is enabled.
12. A digital audio receiver unit having a backup battery for use in an automobile that operates on a primary battery, comprising:
a digital audio receiver (DAR) capable of receiving scheduled data at a predetermined time; and
a controller coupled to the digital audio receiver and programmed to enable the primary battery to power the DAR when the automobile ignition is enabled and to enable the backup battery to power the DAR during at least a portion of the predetermined time to receive the scheduled data when the ignition is disabled.
13. The digital audio receiver unit of claim 12 , wherein the unit further comprises a charging circuit coupled to the backup battery and the primary battery, enabling the primary battery to recharge the backup battery when the automobile is operating.
14. The digital audio receiver unit of claim 12 , wherein the unit further comprise a user input and wherein the scheduled data comprises an index of scheduled program content allowing a user using the user input to select portions of the scheduled program from the index for subsequent downloading over the air.
15. A device for receiving, storing and playing back digital audio radio signals, the device having a backup energy source for use in a vehicle that operates on a primary energy source, comprising:
a receiver for receiving a digitally encoded bit stream over-the-air on a plurality of communication resources, wherein each of the plurality of communication resources contains content and associated index information and wherein the receiver is powered by the primary energy source when the vehicle is operating, wherein the receiver receives data during a predetermined time;
a decoder for selectively decoding a selected plurality of communication resources;
a user input for selecting the selected plurality of communication resources based on the associated index information and for selecting a portion of the content contained in selected plurality of communication resources to be retrieved;
a storage medium coupled to the decoder for storing the content and associated index information contained in the selected plurality of communication resources;
a switching mechanism for switching the receiver between the primary energy source and the backup energy source; and
a system controller coupled to the user input for storing and retrieving content to and from the storage medium based on input received at the user input and for controlling the switching mechanism, wherein the backup energy source powers the receiver during at least a portion of the predetermined time if an ignition of the vehicle is disabled.
16. The device of claim 15 , wherein the device further comprises a charging circuit coupled to the backup energy source and the primary energy source, enabling the primary energy source to recharge the backup energy source when the vehicle is operating.
17. The device of claim 15 , wherein the backup energy source and the primary energy source are batteries.