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US 6,308,050 B1Granted
Dual band mobile phone using the same intermediate frequency for both bands
AssigneeMotorola, Inc.
InventorAnders Eklof
Life of this patent
Estimating the term…
Abstract
A radio which can operate in two separate frequency bands, with size, weight, and cost that is comparable with a conventional unit that can operate in only one frequency band. The radio includes two local oscillators which respectively produce signals at substantially the same frequencies for operation in both frequency bands. By appropriately choosing the frequency of the oscillators' signals, the radio can produce an intermediate signal which has the same frequency when the radio is operating in either band.
Claims12
A method for operating a dual band radio in first and second frequency bands, said method comprising:
- receiving a carrier signal using a receiver, said receiver carrier signal being centered around a frequency f1r when said radio operates in said first frequency band and a frequency f2r when said radio operates in said second frequency band;
- transmitting a carrier signal using a transmitter, said transmitter carrier signal being centered around a frequency f1t when said radio operates in said first frequency band and a frequency f2t when said radio operates in said second frequency band to thereby form a first frequency separation S1 between the frequencies f1t and f1r when said radio operates in said first frequency band and a second frequency separation S2 between the frequencies f2t and f2r when said radio operates in said second frequency band;
- providing a first oscillator signal having a first frequency to both said receiver and said transmitter;
- and
- providing a second oscillator signal having a second frequency to both said receiver and said transmitter;
- wherein said first frequency of said first oscillator signal is set to (f1t+f2t)/2 so that said receiver produces a first reception intermediate signal having a first frequency when said radio operates in said first frequency band and a second frequency when said radio operates in said second frequency band, and said first and second frequencies of said first reception intermediate signal differ by S1+S2.
3 more elements
A dual band radio capable of operating in separate first and second frequency bands, said dual band radio comprising:
- a reception circuit for accepting a received carrier signal;
- a transmission circuit for providing a transmit carrier signal;
- a first oscillator inputting a first oscillator signal having a first frequency to both said reception circuit and said transmission circuit;
- and
- a second oscillator inputting a second oscillator signal having a second frequency to both said reception circuit and said transmission circuit;
- wherein said reception circuit produces an intermediate signal which has the same frequency when the radio operates in either of said first or second frequency bands, and wherein said received carrier signal is centered around a frequency f1r when said radio operates in said first frequency band and a frequency f2r when said radio operates in said second frequency band;
- said transmit carrier signal is centered around a frequency f1t when said radio operates in said first frequency band and a frequency f2t when said radio operates in said second frequency band to thereby form a first frequency separation S1 between the frequencies f1t and f1r when said radio operates in said first frequency band and a second frequency separation S2 between the frequencies f2t and f2r when said radio operates in said second frequency band;
- and
- wherein said first frequency of said first oscillator signal is set to (f1t+f2t)/2.
6 more elements
A dual band mobile phone capable of operating in separate first and second frequency bands, said dual band mobile phone comprising:
- a reception circuit for accepting a received carrier signal;
- a transmission circuit for providing a transmit carrier signal;
- a first oscillator inputting a first oscillator signal having a first frequency to both said reception circuit and said transmission circuit;
- and
- a second oscillator inputting a second oscillator signal having a second frequency to both said reception circuit and said transmission circuit;
- wherein said reception circuit produces an intermediate signal which has the same frequency when the mobile phone operates in either of said first or second frequency bands;
- said received carrier signal being centered around a frequency f1r when said mobile phone operates in said first frequency band and a frequency f2r when said mobile phone operates in said second frequency band;
- said transmit carrier signal being centered around a frequency f1t when said mobile phone operates in said first frequency band and a frequency f2t when said mobile phone operates in said second frequency band to thereby form a first frequency separation S1 between the frequencies f1t and f1r when said mobile phone operates in said first frequency band and a second frequency separation S2 between the frequencies f2t and f2r when said mobile phone operates in said second frequency band;
- and
- said first frequency of said first oscillator signal is set to (f1t+f2t)/2.
7 more elements
A mobile phone comprising:
- a signal reception circuit for accepting a received carrier signal;
- a signal transmission circuit for providing a transmit carrier signal;
- a first oscillator for inputting a first oscillator signal with a first oscillator frequency to said signal reception circuit and said signal transmission circuit;
- and
- a second oscillator for inputting a second oscillator signal with a second oscillator frequency to said signal reception circuit and said signal transmission circuit;
- wherein
- said mobile phone is capable of operating in first and second frequency bands, said first and second frequency bands being separate from each other and said first frequency of said first oscillator signal is the same for mobile phone operation in either of said first and second frequency bands;
- and
- wherein said first frequency of said first oscillator signal is tuneable over a first range;
- and said second frequency of said second oscillator signal is tuneable over a second range, said second range being narrower than said first range.
7 more elements
A radio comprising:
- a signal reception circuit for accepting a received carrier signal;
- a signal transmission circuit for providing a transmit carrier signal;
- a first oscillator for inputting a first oscillator signal with a first frequency to said signal reception circuit and said signal transmission circuit;
- and
- a second oscillator for inputting a second oscillator signal with a second frequency to said signal reception circuit and said signal transmission circuit;
- wherein
- said radio is capable of operating in first and second frequency bands, said first and second frequency bands being separate from each other;
- said first frequency of said first oscillator signal is the same for radio operation in either of said first and second frequency bands;
- and
- said second frequency of said second oscillator signal is substantially the same for radio operation in either of said first and second frequency bands.
7 more elements
Dependencies are inferred from the claim text.