According to one embodiment, a transceiver includes: a radio transmitter including a power amplifier; a detector circuit including: a squaring circuit configured to receive an output of the power amplifier of the radio transmitter and configured to produce an output current; and a DC current absorber electrically connected to an output terminal of the squaring circuit.

Provided is a sine wave multiplication device of simple configuration, broad input signal level range, and minimal fluctuation in characteristics due to temperature. A signal component that corresponds to a product of an input signal Si and the third harmonic wave of a first square wave W1 included in an output signal Su1; and a signal component that corresponds to a product of the input signal Si and the fifth harmonic wave of the first square wave W1 is canceled by: a signal component that corresponds to a product of the input signal Si and the fundamental wave of a second square wave W2 included in an output signal Su2; and a signal component that corresponds to a product of the input signal Si and the fundamental wave of a second square wave W3 included in an output signal Su3.

The present disclosure provides a mixing circuit with high harmonic suppression ratio, including: a multi-phase generation module, which receives a first input signal and generates eight first square wave signals with a phase difference of 45°; a quadrature phase generation module, which receives a second input signal and generates four second square wave signals with a phase difference of 90°; a harmonic suppression module, connected with an output end of the quadrature phase generation module to filter out higher order harmonic components in the second square wave signals; and a mixing module, connected with output ends of the multi-phase generation module and the harmonic suppression module to mix output signals of the multi-phase generation module and the harmonic suppression module. The mixing circuit with high harmonic suppression ratio adds a harmonic suppression module on the basis of multi-phase mixing, thereby improving the harmonic suppression ratio of the output signal.

A cascadable AGC amplifier in a signal distribution system includes a low noise cascadable amplifier having a through path and a cascadable output. The cascadable amplifier is also configured to provide AGC over a predetermined input power range. The cascadable AGC amplifier can be configured to provide gain or attenuation. When the cascadable AGC amplifier is implemented in a signal distribution system, typically as part of a signal distribution device, an input signal can be gain controlled and supplied to multiple signal paths without distortion due to degradation of signal to noise ratio or distortion due to higher order amplifier products. The distributed signal is not significantly degraded by distortion regardless of the number of cascadable AGC amplifiers connected in series or the position of the cascadable AGC amplifier in the signal distribution system.

According to one embodiment, a transceiver includes: a radio transmitter including a power amplifier; a detector circuit including: a squaring circuit configured to receive an output of the power amplifier of the radio transmitter and configured to produce an output current; and a DC current absorber electrically connected to an output terminal of the squaring circuit.

A band-switching network includes a dual-band balun and a switch network. The dual-band balun includes a first output and a second output. The switch network includes a first switch and a second switch in which an input to the first switch is coupled to the first output and an input to the second switch is coupled to the second balanced output. The dual-band balun further includes a primary coil, a first secondary coil and a second secondary coil in which the first secondary coil is coupled to the first balanced output and the second secondary coil is coupled to the second balanced output. In one embodiment, the primary coil and the first secondary coil are coupled by a first coupling factor k.sub.1, and the primary coil and the second secondary coil are coupled by a second coupling factor k.sub.2 that is different from the first coupling factor k.sub.1.

A band-switching network includes a dual-band balun and a switch network. The dual-band balun includes a first output and a second output. The switch network includes a first switch and a second switch in which an input to the first switch is coupled to the first output and an input to the second switch is coupled to the second balanced output. The dual-band balun further includes a primary coil, a first secondary coil and a second secondary coil in which the first secondary coil is coupled to the first balanced output and the second secondary coil is coupled to the second balanced output. In one embodiment, the primary coil and the first secondary coil are coupled by a first coupling factor k.sub.1, and the primary coil and the second secondary coil are coupled by a second coupling factor k.sub.2 that is different from the first coupling factor k.sub.1.

A band-switching network includes a dual-band balun and a switch network. The dual-band balun includes a first output and a second output. The switch network includes a first switch and a second switch in which an input to the first switch is coupled to the first output and an input to the second switch is coupled to the second balanced output. The dual-band balun further includes a primary coil, a first secondary coil and a second secondary coil in which the first secondary coil is coupled to the first balanced output and the second secondary coil is coupled to the second balanced output. In one embodiment, the primary coil and the first secondary coil are coupled by a first coupling factor k.sub.1, and the primary coil and the second secondary coil are coupled by a second coupling factor k.sub.2 that is different from the first coupling factor k.sub.1.

A detector circuit includes: a squaring circuit configured to receive an output of a power amplifier of a radio transmitter and to produce an output current, the output of the power amplifier including: a desired tone; a local oscillator leakage tone; and an image tone, and the output current of the squaring circuit including: a direct current (DC) component including a function of the desired tone and an alternating current (AC) component; and a DC current absorber electrically connected to an output terminal of the squaring circuit, the DC current absorber being configured to filter out the DC component of the output current of the squaring circuit to produce a filtered output of the squaring circuit, the filtered output including the AC component including functions of the local oscillator leakage tone and the image tone.

A device comprises a voltage-mode filter circuit, a current-mode output circuit, and a regulation circuit. The voltage-mode filter circuit is configured to generate a voltage signal on an output terminal thereof. The current-mode output circuit comprises an input transistor which comprises a gate terminal coupled to the output terminal of the voltage-mode filter circuit, and a source terminal coupled to a regulated node. The regulation circuit is configured to adjust a voltage level on the regulated node to maintain a constant gate-source bias voltage for the input transistor to generate a current for biasing the current-mode output circuit.