32results about How to "Improve input dynamic range" patented technology

An RF detector configured to provide two outputs, one being a function of the true RMS power level of an RF input signal, and the other being a function of the instantaneous/peak power of the RF input signal, normalized to the average power level. The RF detector includes a variable gain detection subsystem including a single detector or detector array that provides a representation of the power level of the RF input signal. The detector or detector array is common to both the RMS power detection channel and the instantaneous/peak power detection channel of the RF detector. A method of RF detection includes providing representations of the RF input signal at different gain levels, selecting one or more of the representations, and averaging the selected signals. The gain levels of the selected representations is adjusted to provide information about the average power level of the RF input signal.

The invention discloses a demodulator circuit for a UHF (Ultrahigh Frequency) radio frequency identification label chip. Aiming at the defect of smaller dynamic range brought by the substitution of a traditional grid-grounded MOS (Metal-Oxide Semiconductor) tube for a high-resistance resistor, the invention provides a demodulator circuit which comprises an overvoltage protection circuit and a mean value generating circuit. The demodulator circuit connects the grid of a first PMOS (P-Channel Metal Oxide Semiconductor) tube in the mean value generating circuit with the grid of a first NMOS (N-Channel Metal Oxide Semiconductor) tube in the overvoltage protection circuit, and the grid level of the first PMOS tube automatically varies with the source level thereof by the partial pressure action of a second PMOS tube and a second resistor when the source level of the first PMOS tube rises or falls so that the absolute values of a grid voltage and a source voltage of the first PMOS tube are kept stable, the first PMOS tube has stable equivalent resistance in a large dynamic range, and the demodulator circuit of the invention has greater dynamic input range compared with the traditional demodulator circuit.

The invention provides a low circuit sensitive Sigma-Delta modulator capable of increasing the input signal scope and improving the precision, which comprises a first analog subtractor, a first gain unit, at least one auxiliary quantizer, a second gain unit, a second analog subtractor, a internal Sigma-Delta modulation module, a shift register, a digital subtractor and a feedback digital to analog converter (DAC). The Sigma-Delta modulate not only reduces sensitivity to imperfection of assemblies, but also greatly improves input signal level while improving the precision.

An optical receiver preamplifier includes an inverting amplifier 1 and a current-voltage conversion element 2 connected between input and output terminals of the inverting amplifier 1. The inverting amplifier 1 includes a first transistor 3 having a gate connected to the input terminal In of the inverting amplifier 1, a second transistor 4 having a source connected to a drain of the first transistor 3 and a gate to which a predetermined voltage Vb is applied, and a load 5 connected to a drain of the second transistor 4. A third transistor 6 is connected between the input terminal In of the inverting amplifier 1 and a source of the second transistor 4.

The invention belongs to the technical field of analog integrated circuitry and particularly provides a linear error amplifier with temperature compensation, comprising a PTAT (proportional to absolute temperature) current source, a common collector level shift circuit, a transconductance amplifier composed of an imbalance differential pair, and a frequency compensation network composed of C1, C2 and R1. The common collector level shift circuit raises low voltage to a higher one which is input to a secondary transconductance amplifier; the secondary transconductance amplifier is composed of an imbalance differential pair according to poly-hyperbolic tangent principle, with effective input voltage range widened and linearity improved; the PTAT current source provides tail current for the differential pair to compensate amplifier transconductance instability due to temperature changes; the frequency compensating network generates a suitable zero polar point so that the phase margin of the transconductance amplifiers reaches 60 degrees. The linear error amplifier disclosed herein has a wide dynamic voltage input range and low temperature sensitivity, and is suitable particularly for error amplifiers of DC-DC converters.

The invention discloses an electroencephalogram detection device. The device comprises preamplifying circuits, anti-aliasing filter circuits, analog-to-digital (AD) converters and an analytical computer, and is characterized in that: each of the preamplifying circuits, each of the anti-aliasing filter circuits and each of the AD converters are sequentially connected to form a sampling and AD conversion circuit respectively; a plurality of sampling and AD conversion circuits are connected in parallel to form a plurality of channels of data streams; and then the data streams are collected into a high-speed data stream through a high-speed data collection circuit, and the high-speed data stream is transmitted to the analytical computer for analysis and processing through a data transmission circuit. The invention also discloses an electroencephalogram detection method. By the electroencephalogram detection device, the requirement of simultaneously performing high-rate (10KHZ per channel) and high-precision (24bit) sampling on a plurality of channels of electroencephalogram signals can be met, so that the device has the characteristics of high stability, strong anti-jamming capability, wide frequency band range and the like.

The invention discloses an automatic gain control circuit and method of a transimpedance amplifier circuit. The automatic gain control circuit comprises the transimpedance amplifier circuit, a reference voltage generation circuit and a resistance control circuit; the transimpedance amplifier circuit comprises an input bias resistor circuit, a forward amplifier and a feedback resistor circuit; the reference voltage generating circuit is correspondingly scaled according to the proportion of the transimpedance amplifier circuit and is used for outputting a reference voltage; the resistance control circuit comprises a low-pass filter circuit and a latch comparator, the output voltage of the trans-impedance amplifier passes through the low-pass filter circuit and is compared with the reference voltage through the latch comparator, and the latch comparator generates a digital control bit according to a comparison result, and adjusts the resistance values of the feedback resistance circuit and the input bias resistance circuit through the digital control bit, so the automatic gain control of the trans-impedance amplifier is realized. According to the invention, the dependency relationship between the maximum input current and the feedback resistance is weakened, and the input dynamic range is effectively enlarged.

The invention discloses an oximetry front-end direct-current filtering circuit applicable to a smart band. The oximetry front-end direct-current filtering circuit applicable to the smart band comprises a signal primary input end, wherein the signal primary input end is sequentially connected with a TIA (Totally Integrated Automation) circuit, a controllable bias reduction circuit, a secondary amplifying circuit, an ADC sampling circuit and a processor; a draw-off current circuit is also connected between the signal primary input end and the TIA circuit, and is connected with the processor; the processor is used for controlling the draw-off current circuit to adjust the current signal strength of the signal initial input end. The invention also discloses an adjustment method of the oximetry front-end direct-current filtering circuit applicable to the smart band, and the exposure intensity of an oximetry signal can be further improved without worrying about the saturation of the TIA circuit through adding the draw-off current circuit, so that the dynamic range of the TIA circuit is enlarged in another way. Meanwhile, by the adjustable draw-off current capacity of the draw-off current circuit and a feedback mechanism of the processor, the prime draw-off current capability can be adjusted in real time, and the oximetry front-end direct-current filtering circuit can adapt to different environments.

The invention discloses a front-end circuit for a current input ADC (Analog to Digital Converter). An integrator is arranged between the ADC and a current input end, and the integrator is provided with an integrating capacitor. Particularly, the front-end circuit based on the integrator also comprises an overcurrent discharge circuit which comprises a detection module and a discharge module, wherein the detection module at least comprises a voltage comparator, one input end of the detection module is connected to a voltage output end V1 of the integrator, the other input end of the detection module is connected with a threshold voltage V(thr) of the integrator, the discharge module at least comprises a discharge capacitor C(dis), an electrode plate at one side of the discharge capacitor C(dis) is connected to a positive plate X1 of the integrating capacitor, one electrode plate at the other side of the discharge capacitor C(dis) is connected to a reference voltage end, and the discharge voltage V(f) in the circuit meets the following formula: V(f)=deltaV*C(dis)/C(int), wherein deltaV is the voltage drop of the reference voltage end. According to the front-end circuit disclosed by the invention, the input dynamic range of the current which is input in the ADC is obviously increased under the limit of the capacity of the integrator, the pressure occupied by the inner area of a chip due to the capacity expansion of the integrator is avoided, and a useful solution is supplied for simplifying a lastly connected ADC design.

The invention relates to an air interface analyzing device of a TD-LTE (Time Division-Long Term Evolution) system. The air interface analyzing device of the TD-LTE system comprises an antenna unit, wherein the antenna unit is in wireless RF (Radio Frequency) communication with an RF unit, local oscillator signals of a first local oscillator unit and a second local oscillator unit are output to the RF unit, the output end of the RF unit is connected with the input end of an intermediate frequency unit, the output end of the intermediate frequency unit is connected with the input end of a controller through a transmission unit, and the controller is connected with a display unit which is used for displaying an analyzing result through a signal hierarchical analyzing unit. According to the air interface analyzing device of the TD-LTE system, disclosed by the invention, the power of an input TD-LTE signal can be controlled through the RF unit, and the maximum input signal ability of the TD-LTE signal can be increased; and through the intermediate frequency unit, the input dynamic range of the TD-LTE signal can be increased, the parallel processing can be conducted, the analyzing function of TD-LTE air interface signals of multiple frequency points can be achieved, and the analyzing accuracy of the TD-LTE air interface signals can be increased through the method of separately processing the upstream and the downstream of the TD-LTE signal.