System and apparatus for a direct conversion receiver and transmitter
View Patent ↗A system for transmitting and receiving data is provided. The system includes a direct-conversion receiver that receives a signal modulated on a carrier frequency signal. The direct-conversion receiver includes one or more subharmonic local oscillator mixers. A local oscillator is connected to the direct conversion receiver, and generates a signal having a frequency equal to a subharmonic of the carrier frequency signal. A transmitter is connected to the local oscillator, which uses the local oscillator signal to transmit outgoing data.
1. A system for transmitting and receiving data, comprising:
a direct-conversion receiver with a subharmonic local oscillator mixer for receiving a signal modulated on a carrier frequency signal;
a local oscillator connected to the direct conversion receiver; and
a transmitter, comprising:
a frequency modulator for modulating the local oscillator;
a phase locked loop coupled to the frequency modulator and the local oscillator; and
switch for connecting the phase locked loop to the local oscillator during a transmit cycle and can disconnecting the phase locked loop from the local oscillator during a receive cycle.
2. A system for transmitting and receiving data, comprising:
a direct-conversion receiver with a subharmonic local oscillator mixer for receiving a signal modulated on a carrier frequency signal;
a local oscillator connected to the direct conversion receiver; and
a transmitter, comprising:
a frequency modulator for modulating the local oscillator;
a voltage-controlled reference oscillator connected to the frequency modulator, where the voltage-controlled reference oscillator is modulated by the frequency modulator; and
a phase locked loop connected to the local oscillator in a feedback loop, the phase locked loop further coupled to the voltage controlled oscillator.
3. A system for transmitting and receiving data comprising:
a low noise amplifier receiving a modulated incoming carrier signal having a carrier signal frequency;
a local oscillator generating a local oscillator signal having a local oscillator frequency equal to a subharmonic frequency of the carrier signal such that the local oscillator frequency is 1/N times a frequency of the carrier frequency signal;
a first mixer for generating an in-phase incoming data signal;
a second mixer for generating a quadrature phase incoming data signal;
a frequency multiplier for producing a multiplied local oscillator frequency signal by multiplying the local oscillator signal by N;
a modulator connected to the local oscillator, the modulator receiving an outgoing data signal and modulating the outgoing data signal onto the local oscillator signal using the multiplied local oscillator frequency signal to generate an outgoing modulated carrier signal; and
a transmit amplifier connected to the modulator, the transmit amplifier amplifying the outgoing modulated carrier signal to a transmission power level.
4. The system of claim 3 further comprising a general purpose computing platform connected to the first mixer, the second mixer, and the modulator, the general purpose computing platform decoding an incoming data signal from the in-phase incoming data signal and the quadrature phase incoming data signal, and generating the outgoing data signal.
5. The system of claim 3 further comprising a telephone handset connected to the first mixer, the second mixer, and the modulator, the telephone handset decoding an incoming data signal from the in-phase incoming data signal and the quadrature phase incoming data signal, and generating the outgoing data signal.
6. The system of claim 3 wherein an antenna is directly connected to the low noise amplifier, and the low noise amplifier is directly connected to the one or more subharmonic local oscillator mixers.