US 5,511,236 A · Half duplex RF transceiver

Abstract

A radio frequency (RF) transceiver for modulating and demodulating RF signals with a direct modulation transmitter and a dual intermediate frequency (IF) receiver, respectively, includes a local oscillator, three frequency converters, a demodulator, a carrier generator, a modulator, a controller and two signal switches. The local oscillator (e.g. phase lock loop PLL!) provides a first local oscillator (LO) signal. One frequency converter (e.g. mixer) frequency converts an incoming modulated RF signal with the first LO signal to provide a first modulated IF signal. A second frequency converter frequency converts the first modulated IF signal with a second LO signal to provide a second modulated IF signal. The demodulator also receives the second LO signal and demodulates therewith the second modulated IF signal. The carrier generator (e.g. voltage-controlled oscillator VCO!) receives a transmitter control signal and in accordance therewith generates a transmitter carrier signal. The third frequency converter receives the transmitter carrier signal and the first LO signal and in response thereto provides the second LO signal. The modulator selectively receives and modulates the second LO signal to provide a third modulated IF signal. The controller (e.g. phase detector) receives a reference signal and selectively receives the second LO signal and the third modulated IF signal and in response thereto provides the transmitter control signal. The signal switches receive a mode control signal and in response to one state thereof connect the controller to the third frequency converter and in response to another state thereof connect the modulator to both the third frequency converter and controller.

Claims43

Dependent claims

A radio frequency (RF) transceiver for modulating and demodulating RF signals, said transceiver comprising:

a first local oscillator for providing a first local oscillator (LO) signal;
a dual conversion receiver, coupled to said first local oscillator, for receiving said first LO signal and a second LO signal and in accordance therewith frequency converting and demodulating an incoming modulated RF signal, wherein said frequency converting is done with said first and second LO signals and said demodulating is done with said second LO signal;
and
a transmitter, coupled to said first local oscillator and said dual conversion receiver and including a second local oscillator, for receiving said first LO signal, a reference signal and a mode control signal and in accordance therewith generating and providing said second LO signal, and further for receiving said first LO signal, said reference signal, said mode control signal and at least one modulation signal and in accordance therewith generating and modulating said second LO signal for providing an outgoing modulated RF signal.

1 more element

a local oscillator for providing a first local oscillator (LO) signal;
a first frequency converter, coupled to said local oscillator, for receiving said first LO signal and for receiving and frequency converting therewith an incoming modulated RF signal to provide a first modulated IF signal;
a second frequency converter, coupled to said first frequency converter, for receiving a second LO signal and for receiving and frequency converting therewith said first modulated IF signal to provide a second modulated IF signal;
a demodulator, coupled to said second frequency converter, for receiving said second LO signal and for receiving and demodulating therewith said second modulated IF signal;
a carrier generator for receiving a transmitter control signal and in accordance therewith generating a transmitter carrier signal;
a third frequency converter, coupled to said carrier generator and said local oscillator, for receiving said transmitter carrier signal and said first LO signal and in response thereto providing said second LO signal;
a modulator for selectively receiving and modulating said second LO signal to provide a third modulated IF signal;
a controller, coupled to said carrier generator, for receiving a reference signal and selectively receiving said second LO signal and said third modulated IF signal and in response thereto providing said transmitter control signal;
and
a switchable coupler for receiving a mode control signal and in response thereto coupling said controller to said third frequency converter and coupling said modulator to said third frequency converter and to said controller.

7 more elements

A method for modulating and demodulating RF signals by direct transmission modulation and dual intermediate frequency (IF) reception, respectively, said method comprising the steps of:

providing a first local oscillator (LO) signal;
receiving an incoming modulated RF signal;
frequency converting said incoming modulated RF signal with said first LO signal to provide a first modulated IF signal;
receiving a transmitter control signal and in accordance therewith generating a transmitter carrier signal;
receiving said transmitter carrier signal and said first LO signal and in response thereto providing a second LO signal;
frequency converting said first modulated IF signal with said second LO signal to provide a second modulated IF signal;
demodulating said second modulated IF signal with said second LO signal;
receiving a reference signal;
receiving a mode control signal which includes a plurality of signal states;
in response to a first one of said plurality of mode control signal states, providing said transmitter control signal in accordance with said reference signal and said second LO signal;
and
in response to a second one of said plurality of mode control signal states:
modulating said second LO signal to provide a third modulated IF signal;
and
providing said transmitter control signal in accordance with said reference signal and said third modulated IF signal, whereby said transmitter carrier signal forms an outgoing modulated RF signal.

12 more elements

A method for modulating and demodulating RF signals by direct transmission modulation and dual intermediate frequency (IF) reception, respectively, said method comprising the steps of:

receiving a reference signal;
receiving a mode control signal which includes a plurality of signal states;
providing a first local oscillator (LO) signal;
in response to a first one of said plurality of mode control signal states:
receiving an incoming modulated RF signal;
frequency converting said incoming modulated RF signal with said first LO signal to provide a first modulated IF signal;
receiving a transmitter control signal and in accordance therewith generating a transmitter carrier signal;
receiving said transmitter carrier signal and said first LO signal and in response thereto providing a second LO signal;
frequency converting said first modulated IF signal with said second LO signal to provide a second modulated IF signal;
demodulating said second modulated IF signal with said second LO signal;
providing said transmitter control signal in accordance with said reference signal and said second LO signal;
and
in response to a second one of said plurality of mode control signal states:
receiving said transmitter control signal and in accordance therewith generating said transmitter carrier signal;
receiving said transmitter carrier signal and said first LO signal and in response thereto providing said second LO signal;
modulating said second LO signal to provide a third modulated IF signal;
and
providing said transmitter control signal in accordance with said reference signal and said third modulated IF signal, whereby said transmitter carrier signal forms an outgoing modulated RF signal.

15 more elements

Dependencies are inferred from the claim text.

Half duplex RF transceiver

Life of this patent

Half duplex RF transceiver

Life of this patent

Abstract

Claims43