Patent Application
20070275664
In the following detailed description of the invention, reference is made to the drawings in which reference numerals refer to like elements, and which are intended to show by way of illustration specific embodiments in which the invention may be practiced. It is understood that other embodiments may be utilized and that structural changes may be made without departing from the scope and spirit of the invention.
Referring now to
Referring to
Logical decision device 140 can be a simple comparator circuit, a more complex device such as a microprocessor, a field programmable gate array (FPGA) or a complex programmable logical device (CPLD). Power detector 135 may be an analog or digital device as is known in the art. A detected power bus 150 and a state selection bus 145 carry the control signal generated by logical decision device 140 to RF switches 115 to control operation. Detected power bus 150 may be a single wire or a circuit board trace in cases where power detection features a single analog value output, or a set of traces over which a base-two number is conveyed if a digital output is used.
The RF power level produced by power detector 135 is based on the signal power level produced by directional coupler 130. Directional couplers are well known in the art and route power between separate ports based on the direction of the power flow. Directional coupler 130 conveys a reduced amplitude portion of the RF signal produced by RF transceiver 200 to power detector 135 and the magnitude-time function of the signal is presented to logical decision device 140.
Logical decision device 140 detects either transmit or receive mode based on the measures transceiver 200 output power. Logical decision device 140 produces a control signal transmitted by state selection bus 145 which drives the state of one or more of RF switches 115. One set of RF switch 115 positions will result in transmit mode, while another set of RF switch 115 positions will result in receive mode.
RF transceivers produce much higher levels of output power when in transmit mode; therefore when transceiver 200 is in transmit mode, a large amount of RF power will be at an RF transceiver port 155, thus allowing unit 100 to properly ascertain the proper operating mode. The electronic functions necessary to detect and control unit 100 may use any appropriate modulation format as is known in the art. This allows the present invention to be integrated with any known RF transceivers without modification.
In transmit mode, the transmit signal from transceiver 200 is routed to transmit/receive antenna 210 or 225 respectively which bypasses low noise amplifiers 120 which isolates transmit signals from receive only antennas 205 or 230. This ensures that unit 100 will operate within legal power limits. Various methods are available to guarantee operation within legal limits. A common method includes limiting the effective isotropic radiated power (EIRP) of a transmitting device. The EIRP of a transmitter is the product of the maximum directional gain of the antenna with the RF power level produced at the transmit port terminal of the transmitter. In an embodiment of the present invention, scaling of transmitting RF power to meet legal EIRP limits is accomplished by selecting an appropriate external antenna.
In receive mode, all ports including transmit/receive port 105 and receive only port 110 are active. The received signal are amplified by low noise amplifiers 120 and then combined in an RF power combiner 125. External antennas 205 and 230 have a much higher gain than antennas 210 and 225 used in the transmit mode, which greatly improves the range and performance of the system. All RF connections may be micro strip printed circuit board traces or connectorized coaxial transmission lines as is known in the art.
The advantages of the present invention are illustrated by the following example: A transceiver is used which operates with a regulated EIRP of 6 Watts. In such an instance, RF transceivers would be limited to a 6 dB gain antenna. A similar transceiver operating in accordance with the present invention, would be able to utilize antennas with 30 dB of gain (which are readily available in the US 2.4 GHz range). By operating in accordance to the system illustrated in
Now referring to
With reference to
Antennas may be any suitable configuration and type such as high-gain, low-gain, narrow-band, wide-band, singularly-polarized and multi-polarized as is known in the art.
Although the instant invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art.
This application claims priority and herein incorporates by reference U.S. provisional patent application 60/809,050, filed May 26, 2006.
| Number | Date | Country | |
|---|---|---|---|
| 60809050 | May 2006 | US |
