Multi-Port Receiver

• US 20090267746A1
• Filed: 04/23/2008
• Published: 10/29/2009
• Est. Priority Date: 04/23/2008
• Status: Abandoned Application

• Current Assignee: Martec Corporation
• Original Assignee: Martec Corporation
• Inventors: MUCHKAEV, Artem
• Application Number:
  US12/108,322
• Publication Number:
  US 20090267746A1
• Time in Patent Office: Days
• US Class Current: 340/10.400
• CPC Class Codes: H04L 27/38 Demodulator circuits; Receiver circuits
• CPC Class Codes: H04Q 9/00 Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom

Abstract

A multi-port receiver with a sophisticated signal processing technique for demodulating radiofrequency (RF) modulated digital signals that simplifies the multi-port receiver hardware. A section of a transmission line with coupling probes is used as a six-port circuit. Fixed probes distributed along the transmission line sample the resulting wave pattern at different phase shifts and the outputs of the probes are connected to power detectors. Statistical digital processing of the detector outputs recovers the transmitted signal. Power dividers and hybrid couplers are not required.

Claims

1. A receiver for demodulating RF modulated signals, comprising:

an analog front end having an input and an output;

a multi-port circuit having input ports and output ports; and

a digital back end having power detectors, analog-digital converters and a digital processing unit, wherein

the RF modulated signals are electrically connected to the input of the analog front end;

the output of the analog front end is electrically connected to a first input port of the multi-port circuit;

the output ports of the multi-port circuit are electrically connected to the power detectors of the digital back end;

the power detectors output detected signals that are digitized by the analog-digital converters;

the analog-digital converters output digital observations to the digital processing unit; and

the digital processing unit implements numerical computing methods with iterative procedures to solve an optimization problem.

2. The receiver of claim 1 wherein the multi-port circuit is a section of a transmission line, and the output ports are probes that sample different points on the transmission line.

3. The receiver of claim 2 wherein a local oscillator is electrically connected to a second input port of the multi-port circuit.

4. The receiver of claim 2 wherein the RF modulated signal is a microwave or higher frequency signal.

5. The receiver of claim 4 wherein the RF modulated signal is an ultra wideband signal.

6. An RFID system, comprising:

a transponder having an antenna, a sensor, a modulator and a variable input impedance; and

an RFID reader having an antenna, a local oscillator, a multi-port circuit, and a digital back end, the digital back end including power detectors, analog-digital converters and a digital processing unit, wherein

the REID reader antenna is electrically connected to the multi-port circuit, the local oscillator transfers RE power to the multi-port circuit, the power detectors detect power levels within the multi-port circuit and output detected signals that are digitized by the analog-digital converters;

the analog-digital converters output digital observations to the digital processing unit;

the digital processing unit implements numerical computing methods with iterative procedures to solve an optimization problem; and

the RFID reader, antenna emits RF power that is variably reflected by the transponder and received by the RFID reader.

7. The RFID system of claim 6 wherein the RFID reader includes two to four power detectors, and the multi-port circuit is a section of a transmission line.

8. The RFID system of claim 6 wherein the RFID reader has multiple antennas.

9. The RFID system of claim 6, wherein the RFID reader further comprises a directional coupler having a decoupled port, a matched port, an input port and an output port, wherein

the decoupled port is electrically connected to a first port of the multi-port circuit through a bandpass filter and a low noise amplifier;

the matched port is electrically connected to a second port of the multi-port circuit;

the input port is electrically connected to the local oscillator; and

the output port is electrically connected to the RFID reader antenna.

10. An RFID system, comprising:

a transponder having an antenna, a sensor, a modulator and a variable input impedance;

an RFID reader having an antenna, a local oscillator, a multi-port circuit, a directional coupler having a decoupled port, a matched port, an input port and an output port, and a digital back end having power detectors, analog-digital converters and a digital processing unit, wherein

the decoupled port of the directional coupler is electrically connected to a first port of the multi-port circuit through a bandpass filter and a low noise amplifier;

the matched port of the directional coupler is electrically connected to a second port of the multi-port circuit;

the input port of the directional coupler is electrically connected to the local oscillator;

the output port of the directional coupler is electrically connected to the RFID reader antenna;

the power detectors detect power levels within the multi-port circuit and output detected signals that are digitized by the analog-digital converters;

the analog-digital converters output digital observations to the digital processing unit;

the digital processing unit implements numerical computing methods with iterative procedures to solve an optimization problem;

the RFID reader antenna emits RF power that is variably reflected by the transponder and received by the RFID reader.

11. The RFID system of claim 10 wherein the RFID reader includes two to four power detectors, and the multi-port circuit is a section of a transmission line.

12. The RFID system of claim 10 wherein the RFID reader has multiple antennas.