Generating local oscillator signals for downconversion
OwnerCharles J. Persicoinventor
Life of this patent
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Abstract
A local oscillator signal for direct downconversion is generated using an upper frequency oscillator signal and a lower frequency oscillator signal, both of which have frequencies different from a frequency of an RF input signal. The local oscillator signal thus generated has a frequency that is either the sum or the difference of the frequencies of the upper and lower frequency oscillator signals. As a result, the risk of local oscillator signals re-radiating and coupling the RF signal input is significantly reduced. In addition, in QPSK systems, a quadrature local oscillator signal can be generated with accurate phasing relative to an in-phase local oscillator signal.
Claims32
A method comprising:
- receiving a first signal having a first frequency and a second signal having a second frequency, the first and second frequencies being different from a frequency of an incoming RF signal;
- generating at least one local oscillator signal having a frequency determined as a function of the first and second frequencies;
- and
- generating at least one baseband signal as a function of the local oscillator signal and the RF signal.
A wireless communication device comprising:
- a downconverter to generate at least one baseband signal as a function of an RF signal and of a local oscillator signal, the local oscillator signal having a frequency determined as a function of first and second frequencies different from a frequency of the RF signal;
- and
- a modem to demodulate the at least one baseband signal.
A demodulator comprising:
- a quadrature signal generator to generate in-phase and quadrature local oscillator signals having a frequency determined as a function of first and second frequencies different from a frequency of an incoming RF signal;
- a first mixer to generate an in-phase baseband signal as a function of the in-phase local oscillator signal and the RF signal;
- a second mixer to generate a quadrature baseband signal as a function of the quadrature local oscillator signal and the RF signal;
- and
- a modem to demodulate the in-phase and quadrature baseband signals.
An integrated circuit comprising:
- a quadrature signal generator to generate in-phase and quadrature local oscillator signals having a frequency determined as a function of first and second signals having first and second frequencies different from a frequency of an RF signal;
- a downconverter to generate in-phase and quadrature baseband signals as a function of the RF signal and of the in-phase and quadrature local oscillator signals;
- and
- a modem to demodulate the in-phase and quadrature baseband signals.
A processor readable medium containing processor executable instructions for:
- receiving a first signal having a first frequency and a second signal having a second frequency, the first and second frequencies different from a frequency of an RF signal;
- generating at least one local oscillator signal having a frequency determined as a function of the first and second frequencies;
- and
- generating at least one baseband signal as a function of the at least one local oscillator signal and the RF signal.
A wireless communication device comprising:
- a downconverter configured to
- receive a first signal having a first frequency and a second signal having a second frequency, the first and second frequencies different from a frequency of an RF signal,
- generate at least one local oscillator signal having a frequency determined as a function of the first and second frequencies, and
- generate at least one baseband signal as a function of the at least one local oscillator signal and the RF signal;
- and
- a modem to demodulate the at least one baseband signal.
An apparatus comprising:
- means for receiving a first signal having a first frequency and a second signal having a second frequency, the first and second frequencies different from a frequency of an RF signal;
- means for generating at least one local oscillator signal having a frequency determined as a function of the first and second frequencies;
- and
- means for generating at least one baseband signal as a function of the at least one local oscillator signal and the RF signal.
Dependencies are inferred from the claim text.