A low-noise directional amplifier includes a first port, a second port, a first coupler and a second coupler. The first port is coupled to a first coupler. The low-noise directional amplifier also includes at least two phase preserving amplifiers, a first phase preserving amplifier connected to the first coupler and a second coupler, and the second phase preserving amplifier connected to the first coupler and the second coupler.

A low-noise directional amplifier includes a first port, a second port, a first coupler and a second coupler. The first port is coupled to a first coupler. The low-noise directional amplifier also includes at least two phase preserving amplifiers, a first phase preserving amplifier connected to the first coupler and a second coupler, and the second phase preserving amplifier connected to the first coupler and the second coupler.

A frequency dependent dynamic range control method is employed in a signal emitting system characterized by lower impedance in the high frequency region. An efficient technique is implemented to dynamically estimate current spectrum and conditioning parameters to lower the current in the high frequency region. The method advantageously avoids current overloading without using a series resistor as a current limiter.

A frequency dependent dynamic range control method is employed in a signal emitting system characterized by lower impedance in the high frequency region. An efficient technique is implemented to dynamically estimate current spectrum and conditioning parameters to lower the current in the high frequency region. The method advantageously avoids current overloading without using a series resistor as a current limiter.

A traveling wave parametric amplifier involving a series of Josephson junctions is disclosed. Devices and systems incorporating traveling wave parametric amplifiers, and methods of using and fabricating traveling wave parametric amplifiers are also disclosed. In accordance with one or more aspects, traveling wave parametric amplifiers, devices and systems incorporating traveling wave parametric amplifiers, and methods of using and fabricating traveling wave parametric amplifiers are disclosed.

A traveling wave parametric amplifier involving a series of Josephson junctions is disclosed. Devices and systems incorporating traveling wave parametric amplifiers, and methods of using and fabricating traveling wave parametric amplifiers are also disclosed. In accordance with one or more aspects, traveling wave parametric amplifiers, devices and systems incorporating traveling wave parametric amplifiers, and methods of using and fabricating traveling wave parametric amplifiers are disclosed.

A variable gain amplifier circuit including a first amplifier, a second amplifier, and a variable capacitor connected in series between the first amplifier and the second amplifier is disclosed. As a gain of the variable gain amplifier circuit varies, the input impedance, output impedance, noise figure and third-order output intercept point (OIP3) of the variable gain amplifier circuit remain unchanged.

A variable gain amplifier circuit including a first amplifier, a second amplifier, and a variable capacitor connected in series between the first amplifier and the second amplifier is disclosed. As a gain of the variable gain amplifier circuit varies, the input impedance, output impedance, noise figure and third-order output intercept point (OIP3) of the variable gain amplifier circuit remain unchanged.

A variable gain amplifier circuit including a first amplifier, a second amplifier, and a variable capacitor connected in series between the first amplifier and the second amplifier is disclosed. As a gain of the variable gain amplifier circuit varies, the input impedance, output impedance, noise figure and third-order output intercept point (OIP3) of the variable gain amplifier circuit remain unchanged.

A variable gain amplifier circuit including a first amplifier, a second amplifier, and a variable capacitor connected in series between the first amplifier and the second amplifier is disclosed. As a gain of the variable gain amplifier circuit varies, the input impedance, output impedance, noise figure and third-order output intercept point (OIP3) of the variable gain amplifier circuit remain unchanged.