Radio front end
View Patent ↗A radio front end utilizes at least one band pass filter to pass only the appropriate frequency band. Once the desired frequency band has been isolated it is converted to a digital format in an analog to digital converter and a digital signal processing device interprets the signal.
1. A radio front end comprising:
no more than one radio frequency antenna;
a first filter connected to said antenna for passing a first range of radio frequencies comprising an entire radio frequency band;
a second filter connected to said antenna for passing a second range of radio frequencies comprising an entire radio frequency band;
a device for selecting between said first and second filters;
each of said first range of radio frequencies and said second range of radio frequencies comprising at least a portion of frequencies not encompassed by the other of said first range of frequencies and said second range of frequencies;
an analog to digital converter for receiving said entire radio frequency band from said at least one filter and outputting an output signal;
said analog to digital converter being connected between said at least one filter and a digital signal processing unit; and
said digital signal processing unit for receiving the output signal of said analog to digital converter.
2. The radio front end of claim 1 wherein said first range of frequencies comprises a range of FM radio frequencies.
3. The radio front end of claim 1 wherein said second range of frequencies comprises a range of AM radio frequencies.
4. The radio front end of claim 1 , including:
a first amplifier for scaling the magnitude of an output of said first filter; and
a second amplifier for scaling the magnitude of an output of said second filter.
5. The radio front end of claim 1 , wherein a frequency range passed by said first filter is a fixed range and a frequency range passed by said second filter is a fixed range.
6. A method for preparing a radio signal for digital signal processing comprising:
receiving an analog signal;
passing said analog signal through a first and second fixed frequency range filter, wherein said first fixed frequency range filter passes a first range of radio frequencies comprising an entire radio frequency band, said second fixed frequency range filter passes a second range of radio frequencies comprising an entire radio frequency band, and each of said first range of radio frequencies and said second range of radio frequencies comprising at least a portion of frequencies not encompassed by the other of said first range of frequencies and said second range of frequencies;
selecting between the output of said fixed frequency range filter and said second fixed frequency range filter and passing a selected output to an analog to digital converter;
converting the analog signal to a digital signal; and
sending the digital signal to a digital signal processor.
7. The method of claim 6 including the step of altering the magnitude of the analog signal to a desired magnitude.
8. The radio front end of claim 2 , wherein said FM radio frequencies comprise a range of frequencies of 87 MHz to 108 MHz.
9. The radio front end of claim 3 , wherein said AM radio frequencies comprise a range of frequencies of 520 KHz to 1710 KHz.
10. The radio front end of claim 1 , wherein each of said first filter and said second filter are directly connected to said radio frequency antenna.
11. The radio front end of claim 1 , wherein said device for selecting between said first and second filters comprises a switch connecting each of said first filter and said second filter to said analog to digital converter, such that said switch controls a connection between each of said first filter and said second filter and said analog to digital converter.
12. The method of claim 6 , wherein said step of passing said analog signal through a second fixed frequency range filter occurs simultaneous to said step of passing said analog signal through a first fixed frequency range filter.