Method and apparatus for adjusting the cadence of music on a personal audio device
Disclosed is an audio device that adjusts the cadence of played songs. A user sensor determines cadence data based on movement of the user. A desired cadence is determined based on the cadence data received from the sensor. The cadence of songs is determined by low pass filtering digital representations of the songs and determining the period (T) of the back beat of the songs. An adjustment of the period (T) of the songs is then determined such that the adjustment of the period (T) of the songs results in the songs having the desired cadence. The period (T) of the back beat of the subsequent songs are then adjusted.
1. An apparatus for adjusting the cadence of played songs comprising:
a desired cadence determination circuit for determining a desired cadence based on received cadence data;
a period determination circuit for determining a period of a back beat of at least one song;
a period adjustment circuit for receiving said period of the back beat of said at least one song and said desired cadence, and determining a period adjustment signal based on the period of the back beat of said at least one song and said desired cadence; and
a CODEC for receiving said adjustment signal and said digital representation of said at least one song and adjusting the cadence of said at least one song based on said period adjustment signal;
wherein the cadence is adjusted by an amount determined as a function of said period of the back beat of said at least one song, said desired cadence and a clock rate of the CODEC.
2. The apparatus of claim 1 wherein said period adjustment signal specifies interpolation of a digital representation of said at least one song in order to increase said period of the back beat of said at least one song.
3. The apparatus of claim 1 wherein said period adjustment signal specifies decimation of a digital representation of said at least one song in order to decrease said period of the back beat of said at least one song.
4. The apparatus of claim 1 wherein said amount is calculated at least in part by dividing a difference between the period of the back beat of said at least one song and the desired cadence by a reciprocal of said clock rate.
5. The apparatus of claim 1 further comprising a memory for storing digital representations of songs.
6. The apparatus of claim 1 further comprising a low pass filter for receiving a digital representation of at least one song and generating a signal received by the period determination circuit.
7. A personal audio device comprising the apparatus of claim 1 .
8. A method for adjusting the cadence of played songs, the method comprising the steps of:
determining a desired cadence based on received cadence data;
determining a period of a back beat of at least one song;
determining a period adjustment signal based on the period of the back beat of said at least one song and said desired cadence; and
adjusting the cadence of said at least one song based on said period adjustment signal;
wherein the cadence is adjusted by an amount determined as a function of said period of the back beat of said at least one song, said desired cadence and a clock rate of a CODEC.
9. The method of claim 8 wherein the adjusting step is performed by the CODEC.
10. The method of claim 8 wherein said period adjustment signal specifies interpolation of a digital representation of said at least one song in order to increase said period of the back beat of said at least one song.
11. The method of claim 8 wherein said period adjustment signal specifies decimation of a digital representation of said at least one song in order to decrease said period of the back beat of said at least one song.
12. The method of claim 8 wherein said amount is calculated at least in part by dividing a difference between the period of the back beat of said at least one song and the desired cadence by a reciprocal of said clock rate.
13. The method of claim 8 wherein said cadence data is received from a sensor associated with a user's shoe.
14. The method of claim 8 wherein said cadence data is received from a sensor integrated in an exercise machine.
15. The method of claim 8 wherein the desired cadence is an actual cadence of the user.
16. The method of claim 8 wherein the desired cadence is a multiple of an actual cadence of the user.
17. The method of claim 8 wherein the desired cadence is a factor of an actual cadence of the user.
18. The method of claim 8 wherein determining the desired cadence comprises measuring an actual cadence at a plurality of times and averaging the measured actual cadences.
19. The method of claim 8 wherein determining the desired cadence comprises measuring an actual cadence over a sliding time window and averaging the measured actual cadences.
20. The method of claim 8 wherein the desired cadence is periodically updated.