Patent Application
20090047919
1. Field of the Invention
The present invention relates to audio entertainment systems and more specifically to audio entertainment systems for automobiles.
2. Description of the Known Technology
Portable audio devices, such as audio devices that utilize solid state memory or a hard disk for storage, such as the iPod from Apple, Inc. of Cupertino, Calif., generally provide audio to the user via a set of earphones. If the user wishes to use the portable audio device while operating an automobile, the user must either use the provided earphones or connect the portable audio device to the automobile's entertainment system.
The first solution of simply using the provided earphones poses several problems, including not allowing others within the cabin of the automobile to listen to the portable audio device. Other solutions involve providing audio signals from the portable audio device to the entertainment system of the automobile, thereby utilizing the speakers already found within the automobile. This is generally accomplished by interfacing the output jack of the portable audio device to an input of the entertainment system. The input of the entertainment system may be a cassette deck, or an auxiliary input, such as a jack. However, there are drawbacks to this solution as well. Using the cassette deck of the entertainment system via an adaptor has become problematic because most automobile manufacturers are phasing out cassette decks. As to interfacing with the entertainment system via an auxiliary port, many automobile manufacturers have yet to provide auxiliary inputs as standard equipment.
Another solution for interfacing with the entertainment system of the automobile involves modulating audio signals from the portable audio device. Generally, this is accomplished by attaching a modulator to the output jack of the portable audio device, which then modulates the audio signals such that the signals can be received by the FM tuner found in the entertainment system of the automobile. Unlike a cassette deck or an auxiliary input, virtually all automobiles have entertainment systems capable of receiving FM signals, thereby allowing these automobiles to interface with the portable audio device via such a device.
However, several additional steps are required when utilizing a modulator. The user must first select a radio frequency in which the modulator will transmit the audio signals from the portable audio device. Thereafter, the user must then tune the entertainment system of the automobile to correspond with the previously selected frequency.
In overcoming the drawbacks and limitations of the prior art, an improved entertainment system capable of interfacing with a modulated audio device is described. The entertainment system includes a tuner in communication with an antenna, a processor in communication with the tuner and an audio output device in communication with the processor. The processor is configured to instruct the tuner to tune into one or more radio frequencies, while the audio output device is configured to output an audio signal based on the one or more radio frequencies received by the tuner.
A memory unit containing processor executable instructions is in communication with the processor. The processor executable instructions contained within the memory unit configure the processor to tune the tuner to a predetermined frequency, determine if a signal is present at the predetermined frequency and output an audio signal based on the predetermined frequency to an audio output device if a signal is present at the predetermined frequency.
Further objects, features and advantages of this invention will become readily apparent to persons skilled in the art after a review of the following description, with reference to the drawings and claims that are appended to and form a part of this specification.
Referring to
Referring to
An audio output device 24 is in communication with the processor 14 of the entertainment system 12. The audio output device 24 includes an amplifier 26 and at least one speaker 28. The audio output device 24 is configured to output an audio signal based on one or more of the frequencies received by the tuner 16. The amplifier 26 receives the appropriate signal from the tuner 16 via the processor 14 and amplifies the signal such that the speaker 28 can audibly broadcast the signal so that the occupant located within the occupant compartment 10 can listen.
A modulated audio device 30 includes a portable audio device 32 and a modulator 34 in communication with the portable audio device 32. The portable audio device 32 outputs an audio device signal to an output jack 36. An input jack 38 of the modulator 34 receives the audio device signal from the output jack 36, in which the modulator 34 outputs a radio wave 40 at a predetermined frequency. The predetermined frequency of the modulator 34 can be a fixed frequency or may be a user selectable frequency. Generally, the predetermined frequency is transmitted on the FM band and is therefore capable of being received by the antenna 22 of the entertainment system 12.
The memory unit 20 contains a set of processor executable instructions to configure the processor 14. As later described, the processor executable instructions configure the processor 14 to tune the tuner 16 to a predetermined frequency, determine if a signal is present at the predetermined frequency, and output audio signal based on the predetermined frequency to the audio output device 24 if a signal is present at the predetermined frequency.
Referring to
Thereafter, in step 50, a determination is made if a signal is present at the predetermined audio frequency. This can be determined through a variety of different ways that are well known in the art. One way involves measuring the signal strength of the radio frequency within the channel. If the signal strength is above a certain threshold, a determination is made that a signal is present. Another way involves determining the amount of noise present at the predetermined frequency. If the amount of noise is low, a determination is made that a signal is present. Finally, another way involves looking at the frequency before demodulation and counting the number of zero crossings within a certain range and time window. Of course, it should be understood that these three methods may be used individually or in concert with one another to increase the robustness of the system. If a signal is present at the predetermined frequency, an audio signal based on the predetermined frequency will be outputted to the audio output device 24 as shown in step 52. Otherwise, the method continues to step 54.
In step 54 a determination is made if the entertainment system 12 is in a tuning mode or a non-tuning mode. The tuning mode is when the audio output device 24 is outputting an audio signal based on one or more frequencies received via the tuner 16. For example, if the tuner 16 is currently receiving an FM or AM radio station, and is outputting the FM or AM radio station to the audio output device 24, the processor 14 will determine that the entertainment system 12 is in a tuning mode. The processor 14 will determine that the entertainment system 12 is in a non-tuning mode when the audio output device 24 is not outputting an audio signal based on the one or more radio frequencies received by the tuner 16. For example, this would be a situation in which the entertainment system is receiving signals from a secondary source, such as a compact disc player.
If the entertainment system 12 is in a tuning mode, the method 46 waits a predetermined time interval as shown in step 56. By only monitoring the predetermined radio frequency at predetermined intervals, the user will be unaware that the entertainment system 12 has tuned out of the user selected frequency because the amount of time it takes to determine if the predetermined frequency is sufficiently high is fairly short. Returning to step 54, if a determination is made that the entertainment system is in a non-tuning mode, the method returns to step 50. In the non-tuning mode, because the user is utilizing another a secondary source, such as a compact disc player, the user's enjoyment of audio originating from the secondary source will not be affected if the tuner remains turned to the predetermined frequency.
As a person skilled in the art will readily appreciate, the above description is meant as an illustration of implementation of the principles of this invention. This description is not intended to limit the scope or application of this invention and that the invention is susceptible to modification, variation and change, without departing from the spirit of the invention as defined in the following claims.
