Transmit-receive switch apparatus and method
AssigneeThe United States of America as represented by the Secretary of the Navy
InventorMichael T. McCord
Life of this patent
Estimating the term…
Abstract
A transmit-receive (T-R) switch for achieving fast T-R switching times while ensuring that the signal strength of a received signal is not fully coupled. A differential amplifier and an inverting amplifier, both having a coupling resistor as an input is used so that nearly all of the input signal is sensed by an operational amplifier. This technique improves transducer voltage transfer (coupling) ratio from 15-24% to about 100%. The T-R switch architecture is preferably to short-range, single-transducer acoustic ranging systems.
Claims22
A transmit-receive (T-R) switching device for improving time-delay between relay switching times, the switching device comprising:
- a differential receiver for achieving common mode rejection of undesired signals;
- and
- a coupling resistor for coupling a transducer, in a current mode, to the differential receiver such that substantially all of an input signal is sensed by said receiver to reduce signal losses, wherein impedance of said transducer is a part of the differential receiver's gain setting impedances on an input side of said differential receiver.
A transmit-receive (T-R) switching device for improving time-delay between relay switching times, the switching device comprising:
- a differential receiver for achieving common mode rejection of undesired signals;
- a coupling resistor for coupling a transducer, in a current mode, to the differential receiver such that substantially all of an input signal is sensed by said receiver to reduce signal losses;
- and
- said differential receiver including a differential receiver amplifier for receiving echo currents passing through said coupling resistor, wherein said differential receiver amplifier establishes a virtual connection between positive and negative inputs of said receiver amplifier such that resistances connected to said respective positive and negative inputs appear to be in series, wherein time delay between a transmit mode and a receive mode is less than 50 microseconds.
A method for improving time-delay between relay switching times of a transmit-receive (T-R) switch, the method comprising the steps of:
- using a differential receiver for achieving common mode rejection of undesired signals;
- and
- coupling a transducer to the differential receiver using a coupling resistor such that substantially all of an input signal is sensed by said receiver to reduce signal losses.
A method for improving time-delay between relay switching times of a transmit-receive (T-R) switch, the method comprising:
- using an inverting receiver amplifier circuitry for achieving lossless coupling of a transducer's electrical signals, wherein said coupling being a current-mode coupling;
- receiving and converting alternating-current (AC) signals of a first type into acoustic signals of a first type in a transmit mode;
- receiving and converting acoustic signals of a second type into electrical currents of a second type in a receive mode;
- steering electrical currents of the second type to a receiver amplifier for sensing the electrical currents of the second type;
- and
- whereby transducer voltage transfer ratio of inverting receiver amplifier is 100%, and wherein impedance of said transducer is a part of the inverting receiver amplifier's gain setting impedances on an input side of said inverting receiver amplifier.
A method for improving time-delay between relay switching times of a transmit-receive (T-R) switch, the method comprising:
- receiving and converting alternating-current (AC) signals of a first type into acoustic signals of a first type in a transmit mode;
- receiving and converting acoustic signals of a second type into electrical currents of a second type in a receive mode;
- steering electrical currents of the second type to a differential receiver for sensing the electrical currents of the second type;
- and
- coupling a transducer to the differential receiver, in a current mode, using a coupling resistor such that substantially all of said electrical currents of the second type are sensed by said receiver to reduce signal losses, wherein impedance of said transducer is a part of the differential receiver's gain setting impedances on an input side of said differential receiver.
A method for improving time-delay between relay switching times of a transmit-receive (T-R) switch, the method comprising:
- using a receiver having a differential amplifier for achieving common mode rejection of undesired signals;
- coupling a transducer to the differential receiver, in a current mode, using a resistor such that substantially all of an input signal is sensed by said receiver to reduce signal losses, wherein impedance of said transducer is a part of the differential receiver's gain setting impedances on an input side of said differential receiver;
- and
- whereby transducer voltage transfer ratio is provided by
- Vi*(R1+R2+R3)/(Xi+R1+R2+R3)
- where Vi=transducer's received input voltage
- Xi=internal impedance of transducer
- R1, R2=resistance of one leg of differential amplifier
- R3=resistance of a second leg of differential amplifier.
A transmit-receive (T-R) switching device for improving coupled signals, in a current mode, from a sonar transducer to a pre-amplifier, the device comprising:
- a resistor for limiting signals to the pre-amplifier during a transmit mode;
- said resistor passing signals to the pre-amplifier during a receive mode;
- and
- a differential amplifier using said resistor such that substantially all of an input signal is sensed by said receiver to reduce signal losses, wherein impedance of said transducer is a part of the differential amplifier's gain setting impedances on an input side of said differential amplifier.
An apparatus for improving time-delay between relay switching times of a transmit-receive (T-R) switch, comprising:
- means for receiving and converting alternating-current (AC) signals of a first type into acoustic signals of a first type in a transmit mode;
- means for receiving and converting acoustic signals of a second type into electrical currents of a second type in a receive mode;
- means for steering electrical currents of the second type to a differential receiver for sensing the electrical currents of the second type;
- and
- means for coupling a transducer, in a current mode, to the differential receiver using a coupling resistor such that substantially all of said electrical currents of the second type are sensed by said receiver to reduce signal losses, wherein impedance of said transducer is a part of the differential receiver's gain setting impedances on an input side of said differential receiver.
An apparatus for switching signals between a transducer and a receiver in sonar systems, the apparatus comprising:
- a differential receiver for achieving common mode rejection of undesired signals, said receiver including a differential amplifier;
- a resistor for coupling the transducer, in a current mode, to the differential receiver such that substantially all of an input signal is sensed by said receiver to reduce signal losses, wherein impedance of said transducer is a part of the differential receiver's gain setting impedances on an input side of said differential receiver;
- and
- whereby transducer voltage transfer ratio is provided by
- Vi*(R1+R2+R3)/(Xi+R1+R2+R3)
- where Vi=transducer's received input voltage
- Xi=internal impedance of transducer
- R1, R2=resistance of one leg of differential amplifier
- R3=resistance of a second leg of differential amplifier.
Dependencies are inferred from the claim text.