On-chip Multi-band equalizers for adjusting signal strength for a receiver receiving multi-band frequency signals are provided, The multi-band equalizer comprises multiple series connected tapped LC resonators. The tapped LC resonator may be capacitive tapping or inductive tapping, where both frequency and gain of the frequency bands of interest may be programmed by tuning the capacitances of the programmable capacitors and/or selecting the tapped out terminals of the inductors. The multi-band equalizer may be connected to a signal node, for instance between two amplifiers in the receiver.

On-chip Multi-band equalizers for adjusting signal strength for a receiver receiving multi-band frequency signals are provided, The multi-band equalizer comprises multiple series connected tapped LC resonators. The tapped LC resonator may be capacitive tapping or inductive tapping, where both frequency and gain of the frequency bands of interest may be programmed by tuning the capacitances of the programmable capacitors and/or selecting the tapped out terminals of the inductors. The multi-band equalizer may be connected to a signal node, for instance between two amplifiers in the receiver.

A multipath suppression method based on a steepest descent method includes stripping, according to carrier Doppler shift information fed back by a phase-locked loop, a carrier from an intermediate-frequency signal input into a tracking loop; constructing, on the basis of the autocorrelation characteristics of a ranging code, a quadratic cost function related to a measurement deviation of the ranging code, the cost function being not affected by a multipath signal; and finally, designing a new tracking loop of the ranging code according to the quadratic cost function and the principle of the steepest descent method, such that the loop has a multipath suppression function without increasing the computational burden. Compared with a narrow-distance correlation method, the current method reduces computing resources by ⅓, the design and adjustment of parameters are simple and feasible, a multipath suppression effect is superior, and a high engineering application value is obtained.

A radio frequency device has a multifunctional tuner that stores measurements of reflection coefficient parameter in a register. The radio frequency device also has a transceiver that has a transmitter. The transceiver may detect a transmitter signal from the transmitter to an antenna in an initial tuning state and then determine whether the transmitter signal is stable. In response to the transmitter signal being stable, the transceiver may measuring the reflection coefficient parameters at the multifunctional tuner. Furthermore, the radio frequency device has a baseband controller that has a memory to store instructions and a processor to execute the instructions. The instructions cause the processor to determine an antenna impedance based on the reflection coefficient parameters, and in response to determining that the antenna impedance is greater than or less than a threshold antenna impedance, iteratively tune the antenna using the multifunctional tuner.

A network communication device includes a first output port, a second output port, and a converting circuit. The first output port may be in communication with an input port and may be configured to receive a first reduced-power version of the signal received at an input port. The converting circuit may be configured to receive a second reduced-power version of the signal, down-convert a high-frequency portion thereof, and produce a down-converted signal. The first and the second reduced-power versions of the signals are in the same frequency band. The second output port receives at least a portion of the down-converted signal such that the high frequency portion of the second reduced power version of the signal is attenuated before the signal is transmitted to a subscriber device.

A network communication device includes a first output port, a second output port, and a converting circuit. The first output port may be in communication with an input port and may be configured to receive a first reduced-power version of the signal received at an input port. The converting circuit may be configured to receive a second reduced-power version of the signal, down-convert a high-frequency portion thereof, and produce a down-converted signal. The first and the second reduced-power versions of the signals are in the same frequency band. The second output port receives at least a portion of the down-converted signal such that the high frequency portion of the second reduced power version of the signal is attenuated before the signal is transmitted to a subscriber device.

A circuit includes an impedance tuning circuit, a first antenna tuning switch and a resistor. An antenna end of the first antenna tuning switch is electrically connected with an external antenna signal source. A control end of the first antenna tuning switch is electrically connected with an external controller. A first RF output end of the first antenna tuning switch is electrically connected with one end of the resistor, and the other end of the resistor and a second RF output end of the first antenna tuning switch are electrically connected with one end of the impedance tuning circuit. The other end of the impedance tuning circuit is electrically connected with the antenna. The external controller controls the antenna end to be connected with the first RF output end or the second RF output end according to an SAR test result of the antenna.

A circuit includes an impedance tuning circuit, a first antenna tuning switch and a resistor. An antenna end of the first antenna tuning switch is electrically connected with an external antenna signal source. A control end of the first antenna tuning switch is electrically connected with an external controller. A first RF output end of the first antenna tuning switch is electrically connected with one end of the resistor, and the other end of the resistor and a second RF output end of the first antenna tuning switch are electrically connected with one end of the impedance tuning circuit. The other end of the impedance tuning circuit is electrically connected with the antenna. The external controller controls the antenna end to be connected with the first RF output end or the second RF output end according to an SAR test result of the antenna.

A monitor system is provided for wireless communication between a message source and a wearer needing guidance or information from the message source. The monitor system includes a wireless earpiece speaker device. A short-range radio receiver is coupled to the earpiece device. A transceiver in the system includes a long-range radio frequency receiver to receive a long-range radio frequency signal from an ultrahigh frequency (UHF) band source or a very high frequency (VHF) band source. The transceiver also includes a short-range transmitter module that converts the long-range radio frequency signal into a short-range radio frequency signal and communicates the short-range frequency signal to the earpiece speaker device.

A monitor system is provided for wireless communication between a message source and a wearer needing guidance or information from the message source. The monitor system includes a wireless earpiece speaker device. A short-range radio receiver is coupled to the earpiece device. A transceiver in the system includes a long-range radio frequency receiver to receive a long-range radio frequency signal from an ultrahigh frequency (UHF) band source or a very high frequency (VHF) band source. The transceiver also includes a short-range transmitter module that converts the long-range radio frequency signal into a short-range radio frequency signal and communicates the short-range frequency signal to the earpiece speaker device.