257results about How to "Avoid signal distortion" patented technology

The invention discloses a system and method for canceling high-transmission-power same-time same-frequency self-interference under the multi-path environment. The method includes the steps that at the transmitting end, a transmission power control unit is used for controlling radio-frequency signal power of the transmitting end to be a low noise amplifier unsaturated low power value of the receiving end and sending radio-frequency signals of the transmitting end into a radio-frequency interference reestablishing unit I and a radio-frequency interference reestablishing unit II; at the receiving end, and radio-frequency signals output by an antenna unit and the signals processed by the radio-frequency interference reestablishing unit I are subtracted to complete cancellation of radio-frequency self-interference for the first time; then the radio-frequency signal power of the transmitting end is controlled to be a high-power value, and at the receiving end, after the signals enabling the radio-frequency self-interference to be canceled for the first time are amplified by a low noise amplifier, the signals and the signals processed by the radio-frequency interference reestablishing unit II are subtracted to complete cancellation of radio-frequency self-interference for the second time. The system and method for canceling the high-transmission-power same-time same-frequency self-interference under the multi-path environment are suitable for a same-time same-frequency system, improve canceling capacity of high-transmission-power radio-frequency self-interference signals, improve communication stability, and double the spectrum utilization rate.

A linear mixer circuit with a current amplifier has an excellent linearity by using RF open-load and an improved current amplifier. Therefore, a voltage-current converting stage and a current-voltage converting stage in a conventional mixer circuit can be omitted. Further, by using the RF open-load and the current amplifier together, a current type input signal can be transmitted as it is, and non-linearity due to the voltage-current converting stage and the current-voltage converting stage can be prevented. Furthermore, bias current of the amplifying stage and the switching stage can be separated by using the RF open-load, so that an image frequency can be filtered by the RF open-load.

An LCD device provides enhanced display quality. An insulating layer is formed on a first substrate. The insulating layer covers the contact portion of a switching device in which the switching device is electrically connected to a transparent electrode and has an opening for exposing a portion of the transparent electrode. A reflection electrode is electrically connected to the transparent electrode through the opening. The insulation layer covers a first portion of a driving circuit formed on the first substrate. A sealant is interposed between the first and second substrate to engage the first and second substrate and to cover a second portion of the driving circuit. Therefore, the driver circuit may operate normally, and the distortion of the signal outputted from the driver circuit may be prevented.

Hierarchical modulation preferably uses a 16-ary quadrature amplitude modulation (QAM) modulator with a convolutional encoder that combine to effectively provide unequal protection to two different segments of streaming input data, with improved power efficiency with the same bandwidth efficiency, by encoding the first segment as coded data as LSBs as the second segment remains uncoded as uncoded MSBs, with the MSBs used for QAM constellation modest reliability interquadrant demodulation and detection, and with the LSBs used for low reliability intraquadrant detection, but with the LSBs subject to convolutional encoding and decoding rendering the LSBs with high reliability detection, such that, the two segments have unequal coding and modulation for providing unequal levels of reliability detection.

The invention discloses a physiological signal detecting system based on a continuous wave Doppler radar. The physiological signal detecting system comprises a Doppler radar sensor, a power supply module, a signal preprocessing module, a differential amplifier, an active band-pass filter, a breath and heartbeat signal separation module and an MCU module, wherein the Doppler radar sensor is used for transmitting continuous wave radar signals to a human chest and receiving echo signals, processing the echo signals to output low-frequency signals which reflect human respiration and heartbeat change, conducting signal processing on the low frequency signals through the signal preprocessing module, the differential amplifier, the active band-pass filter, the breath and heartbeat signal separation module and the MCU module, and acquiring human breath signals and human heartbeat signals. Through the adoption of the technical scheme, the Doppler radar sensor works in a continuous wave mode and a multistage filter circuit is correspondingly designed, so that the non-contact detection of the human physiological signals can be realized, and the restriction and discomfort feeling of traditional contact type detection equipment to a patient can be avoided.

The invention discloses an automatic gain control method for audio frequency, which presets the initial gain value. The method comprises: check whether the present frame input signal is mute frame signal; if it is a mute frame signal, directly output the present frame input signal; otherwise, process the present frame input signal in an amplification gain device and then output it. Besides, the invention also discloses an automatic gain control device for audio signal. The method and device disclosed in the invention, which do not amplify the background noise and do not produce signal distortion, are able to realize the automatic control of output power in hearing aid under the condition of ensuring the speech resolution ability.

The invention relates to a precompensation method for in-band group delay fluctuation of a satellite navigation signal generating system, which comprises the following steps: (1) measuring a combined S parameter of a modulator, a filter and an amplifier in the satellite navigation signal generating system, and determining amplitude-frequency and group delay characteristic of the combination of the three devices; (2) counting the group delay characteristic of a precompensation filter according to the combined group delay characteristic; (3) obtaining the phase-frequency characteristic of the precompensation filter; (4) setting the phase-frequency characteristic of the precompensation filter to be an inverse Sinc function; (5) obtaining a system function of the precompensation filter according to the amplitude-frequency characteristic and phase-frequency characteristic of the precompensation filter; (6) obtaining a unit impulse response function of the precompensation filter; (7) setting a threshold value, and setting the quantity in the unit impulse response function, which is smaller than the threshold value, to be zero to be as a coefficient of the precompensation filter; and (8) realizing the precompensaiton filter in a digital standalone of the satellite navigation signal generating system by using the coefficient of the precompensation filter, so as to compensate the group delay fluctuation of the satellite navigation signal generating system.

The present invention discloses a loop compensation method. The method includes the following steps that: a switching circuit receives error amplification signals outputted by a switching power source feedback network and outputs the error amplification signals to a lag compensation circuit under the control of a control signal with a predetermined duty ratio; the lag compensation circuit generates compensated signals and transmits the compensated signals to a sampling circuit; and the sampling circuit receives the compensated signals and transmits the compensated signals to a duty ratio control circuit of a switching power source main power switching tube under the control of the other control signal with a predetermined duty ratio. With the loop compensation method of the invention adopted, control circuits can be wholly integrated in control devices, and therefore, the number of peripheral components can be decreased, and power source cost can be decreased, and at the same time, the compensated signals can be stored completely, and therefore, the distortion of the compensated signals when the switching circuit is switched off can be avoided. The invention also discloses a loop compensation circuit corresponding to the above method.

A chip-on-glass (COG) type liquid crystal display device minimizes a reflected wave from an input terminal of a source driver IC, regardless of the resistance value of a transmission line on a glass substrate, through the use of impedance matching at a front terminal of an LOG and impedance matching at an output terminal of a timing controller, thereby enhancing the frequency characteristic while maintaining a slim and lightweight design, so that it is possible to express a high-resolution high-quality image.

A diagnostic interface on a wafer probe card is provided to enable monitoring of test signals provided between the test system controller and one or more DUTs on a wafer during wafer testing. To prevent distortion of test signals on the channel lines, in one embodiment buffers are provided on the probe card as part of the diagnostic interface connecting to the channels. In another embodiment, an interface adapter pod is provided that connects to the diagnostic interface on the probe card to process the test results and provide the results to a user interface such as a personal computer.

A method and an apparatus for controlling gain in a multi-audio channel system as well as a voice processing system are disclosed. The method includes: judging whether signals on any audio channels are similar or correlated; sorting audio channels of similar or correlated signals into one group if the similar or correlated signals exist on the audio channels, and using the same Automatic Gain Control (AGC) unit to process signals of this group of audio channels; and using different AGC units to process other non-similar or non-correlated signals on audio channels. The gain control apparatus includes: a judging unit, a grouping unit, a control processing unit, and at least two AGC units. Therefore, in a multi-audio channel communication, the perception of the sound locations of similar or correlated audio channels is not damaged, and the non-similar or non-correlated audio channels doe not interfere with each other.

A super-high-speed all-optical communication system inclues a signal frequency acquisition circuit, a detection comparison circuit and a frequency modulation output circuit. The signal frequency acquisition circuit collects the signal of the input end of the signal transmission channel of the control end of the ultra-high-speed all-optical communication system, A pi-type filter circuit composed ofan inductor L1, a capacitor C2 and a capacitor C3 is used for filtering, and the detection comparison circuit uses an average detection circuit pair composed of an operational amplifier AR1, an operational amplifier AR2 and a diode D1 to lock the signal in an average range, and simultaneously uses an operational amplifier AR3, an operational amplifier AR4 and a resistor R10 A hysteresis comparison circuit composed of a resistor R13 filters out clutter on the signal, At last, that frequency modulation output circuit use the frequency modulation circuit composed of the transistor Q3, the transistor Q4 and the capacitor C6 to output the frequency modulation signal, so as to prevent the frequency hopping and distortion of the signal. The output signal voltage of the operational amplifier AR4is regulated by the feedback of the transistors Q1 and Q2.

The invention discloses a signal compensation circuit of a pipeline corrosion degree measuring instrument. The signal compensation circuit comprises a frequency collecting circuit, a push-pull buffercircuit and a compensation output circuit; the frequency collecting circuit collects analog signal frequencies when the pipeline corrosion degree measuring instrument works; the push-pull buffer circuit applies a push-pull circuit composed of a triode Q3, a triode Q4, a triode Q5, a diode D4 and a diode D3 to process the signals, meanwhile applies a buffer circuit composed of a resistor R8, a capacitor C4 and a triode Q6 to buffer the signals, and applies a triode Q7 to feed operational amplifier AR1 output signals back to an emitting electrode of the triode Q5, finally, an operational amplifier AR2 amplifies the signals in a noninverting mode and then inputs the signals into the compensation output circuit, finally, the compensation output circuit applies a power supply +10 V and is subjected to pressure dividing through a variable resistor RW2 to compensate operational amplifier AR2 output signals, and applies a resistor R16, a resistor R17, a capacitor C5 and a capacitor C6 to constitute a RC circuit to filter the signals and then output the signals, and the analog signal frequencies can be converted to compensating signals of analog signals of the pipeline corrosion degree measuring instrument.

A mobile wireless terminal (MWT) includes multiple wireless modems. The multiple modems have their respective transmit outputs combined together to produce an aggregate transmit output. The multiple modems can concurrently transmit data in a reverse link direction and receive data in a forward link direction. The MWT is constrained to operate under an aggregate transmit power limit. Each of the multiple modems has an individual transmit limit related to the aggregate transmit power limit. An MWT controller adjusts the individual transmit power limits in the multiple modems based on an aggregate transmit power limit of the MWT and respective transmit power estimates from the modems, to cause each individual transmit power limit to track a corresponding individual modem transmit power.

The invention discloses a Mesh ad-hoc network channel adaptive automatic equalizer which comprises a linear equalizer and a decision feedback equalizer. The linear equalizer is composed of a delayed unit, tap coefficient units, a summing device and a sampling decision device, the tap coefficient unit consists of a noise producing module and a multiplier, outputs of all tap coefficient units are connected with the summing device, and a balance output of the summing device is connected with the sampling decision device. The decision feedback equalizer is composed of a forward direction filter and a feedback filter, the feedback filter consists of a tap coefficient unit and a delayed unit, a balance output of the equalizer is connected with an input of the delayed unit, an output of the delayed unit is connected with an input of the tap coefficient unit, and the outputs of the tap coefficient units are connected with the summing device. When tracking time-variable characteristics of a communication channel in real time, the Mesh ad-hoc network channel adaptive automatic equalizer overcomes the disturbance among symbols, can effectively prevent from producing signal distortion or producing error code on a receiving end in the process of information transport, and improves communication quality of Mesh ad-hoc network.

The invention provides a single carrier frequency domain equalization method of mobile communication of low-orbit satellites, and relates to single carrier frequency domain equalization technology of mobile communication of low-orbit satellites. The single carrier frequency domain equalization method provided by the invention aims at solving the problem of signal distortion of a mobile communication system of low-orbit satellites. In the mobile communication system of the low-orbit satellites, in an IBDFE algorithm, approximate processing is carried out on a received signal that has been processed on the basis of a linear equalization algorithm for one time before decision feedback, iterative equalization output and an MSE in the frequency domain are derived successively, values of an equalization tap coefficient and a feedback filter tap coefficient in an IBDFE equalizer are acquired, and single carrier frequency domain equalization of the mobile communication of the low-orbit satellites is achieved. The single carrier frequency domain equalization method provided by the invention is applicable to the single carrier frequency domain equalization of the mobile communication of the low-orbit satellites.

This invention relates to multi-load communication system, which comprises one multi-load wave signals generation device and one multi-load peak remove device, wherein, the peak remove device is to reduce peak proportion of the multi-load signals generated by the device; the multi-load signals generation device comprises several single load wave signal generation module and sum module; the said remove device comprises hard limit range device, sum device, match filter parameter generation device and match filter process device.