摘要:
The invention provides a receiving system and a transmitting system capable of decreasing an offset between differential signals and between quadrature signals and improving a manufacturing yield and a semiconductor integrated circuit device for processing a wireless communication signal having therein the systems. A receiving system includes: a local oscillator for generating an oscillation signal in a desired frequency; a 90-degree phase-shifting circuit for generating a signal by shifting a phase of the oscillation signal output from the local oscillator by 90 degrees; a first mixer for mixing one of differential reception signals with an output signal of the first 90-degree phase-shifting circuit and outputting frequency-converted differential signals; and a second mixer for mixing another one of the differential reception signals with an output signal of the local oscillator and outputting frequency-converted differential signals.
摘要:
Because there are different voltages at two current output terminals of a current divider, the voltages at the current input terminals of two current switch circuits are not affected mutually even with a large amplitude of local signals. Accordingly, the performance of a quadrature mixer can be enhanced by increasing the amplitude of the local signals. Bias currents are supplied to the two current switch circuits through the current divider from a common DC current source which essentially supplies a bias current to a V/I converter and, therefore, power consumption is reduced.
摘要:
Because there are different voltages at two current output terminals of a current divider, the voltages at the current input terminals of two current switch circuits are not affected mutually even with a large amplitude of local signals. Accordingly, the performance of a quadrature mixer can be enhanced by increasing the amplitude of the local signals. Bias currents are supplied to the two current switch circuits through the current divider from a common DC current source which essentially supplies a bias current to a V/I converter and, therefore, power consumption is reduced.
摘要:
Because there are different voltages at two current output terminals of a current divider, the voltages at the current input terminals of two current switch circuits are not affected mutually even with a large amplitude of local signals. Accordingly, the performance of a quadrature mixer can be enhanced by increasing the amplitude of the local signals. Bias currents are supplied to the two current switch circuits through the current divider from a common DC current source which essentially supplies a bias current to a V/I converter and, therefore, power consumption is reduced.
摘要:
To reduce circuit area and power consumption and suppress transient response occurring at switching in PGA of a programmable gain amplifier is provided a wireless communication receiver comprising PGAs for adjusting the gain of a received signal down-converted by mixers and sending it to base-band block. Within PGAs are provided HPFATT circuits formed of capacitors arranged in series, and ladder resistors arranged in parallel, with signal lines, and a plurality of switches. HPFATT is a circuit serving as a high-pass filter and an attenuator for gain switching, wherein switches are controlled by control signal sg from a controller. Amplifiers connected to the rear stage of the HPFATT circuit are formed of MOS transistors.
摘要:
The invention provides a receiving system and a transmitting system capable of decreasing an offset between differential signals and between quadrature signals and improving a manufacturing yield and a semiconductor integrated circuit device for processing a wireless communication signal having therein the systems. A receiving system includes: a local oscillator for generating an oscillation signal in a desired frequency; a 90-degree phase-shifting circuit for generating a signal by shifting a phase of the oscillation signal output from the local oscillator by 90 degrees; a first mixer for mixing one of differential reception signals with an output signal of the first 90-degree phase-shifting circuit and outputting frequency-converted differential signals; and a second mixer for mixing another one of the differential reception signals with an output signal of the local oscillator and outputting frequency-converted differential signals.
摘要:
A high frequency signal receiver comprising a variable gain amplifier, a first filter for restricting a bandwidth of an analog baseband signal, an AD converter connected to the first filter, a second filter for restricting the bandwidth of an output of the AD converter, an interference wave detection circuit for detecting the level of an interference wave in the received signal, and a controller for controlling the first filter to have a wide bandwidth when the level of the interference wave is lower than a threshold level, and switching the first filter to have a narrow bandwidth while changing the characteristics of the second filter so as to compensate deterioration of the pass-band of the first filter when the level of the interference wave is equal to or greater than the threshold level.
摘要:
There are provided a voltage-controlled oscillator and an RF-IC for W-CDMA, which are capable of ensuring a wide frequency range and improving oscillation stability. The voltage-controlled oscillator (RF-IC) includes: switching A and B inductors generating a magnetic interaction between resonant A and B inductors of a resonant circuit; and an A_NMOS, a B_NMOS, a C_NMOS, and D_NMOS as switch/load means having together a function of changing an inductance value by the magnetic interaction between the resonant A and B inductors and the switching A and B inductors and a function of serving as loads of the switching A and B inductors. The A_NMOS, the B_NMOS, the C_NMOS, and the D_NMOS are turned ON/OFF by a control signal so as to control the mutual induction, whereby the oscillation frequency is switched by changing the inductance value of the resonant circuit. Also, oscillation stability is improved by increasing the inductance value.
摘要:
In a gain switching LNA including a first transistor, a first transistor group (for example, second to ninth transistors) and a second transistor group (for example, tenth to seventeenth transistors), a first resistor connected between an emitter of the tenth transistor and a collector of the first transistor and a second resistor connected to emitters of eleventh to seventeenth transistors and the collector of the first transistor and having a resistance one seventh as high as that of the first resistor are provided. In a high-gain mode, since isolation of the tenth to seventeenth transistors which are turned OFF and the first and second to ninth transistors is secured by the first resistor and the second resistor, there is no deterioration in the noise factor.
摘要:
A quadrature mixer circuit and an RF communication semiconductor integrated circuit capable of suppressing variations in secondary distortion while reducing the current consumption are provided. In a quadrature mixer circuit, even if local signals different by 90 degrees inputted to the bases of I transistors and Q transistors have large amplitudes, interference is suppressed by I resistors, Q resistors, and capacitors. Also, since the capacitors are provided, changes in bias current values can be suppressed. Accordingly, variations in secondary distortion can be suppressed. Furthermore, the capacitors combine current outputs of a differential circuit formed of I transistors and the resistor and a differential circuit formed of Q transistors and the resistor. Therefore, current consumption can also be reduced.