36 results about "Amplifier noise" patented technology

An RNG circuit is connected to the parallel port of a computer. The circuit includes a flat source of white noise and a CMOS amplifier circuit compensated in the high frequency range. A low-frequency cut-off is selected to maintain high band-width yet eliminate the 1 / f amplifier noise tail. A CMOS comparator with a 10 nanosecond rise time converts the analog signal to a binary one. A shift register converts the serial signal to a 4-bit parallel one at a sample rate selected at the knee of the serial dependence curve. Two levels of XOR defect correction produce a BRS at 20 kHZ, which is converted to a 4-bit parallel word, latched and buffered. The entire circuit is powered from the data pins of the parallel port. A device driver interface in the computer operates the RNG. The randomness defects with various levels of correction and sample rates are calculated and the RNG is optimized before manufacture.

In order to reduce the noise components in a multiplexed communication system, noise components generally referred to as splatter that from the rapid transition between the transmitting state and the non-transmitting state, this power transition in the transmitted signal is provided with a ramped envelope. In the preferred embodiment, the ramped power transition is the result of a ramped enabling signal applied to the power amplifier generating the transmitted signal. The use of a ramped power transition reduces the noise introduced as a result of an abrupt power transition. In addition, the transmitted signal is provided with a preamble so that no data is transmitted during the transition period.

Noise reduction for a switching amplifier system having a differential output stage and demodulator filter responsive to complementary PWM signals includes generating in-phase PWM signals and gradually adjusting their duty cycle between a low duty cycle and the full duty cycle of the complementary PWM signals, generating full duty cycle PWM signals and gradually shifting their relative phase between in-phase and out-of-phase; and in response to a turn-on signal, adjusting the in-phase PWM signals from low to full duty cycle and shifting the relative phase from in-phase to out-of-phase, and in response to a turn-off signal shifting the relative phase from out-of-phase to in-phase and adjusting the in-phase PWM signals from full to low duty cycle for maintaining balanced charge on the demodulation filter to reduce audible noise.

An amplifier (10) includes a first stage (4) including differentially coupled first (Q1) and second (Q2) input transistors and a controlled active load circuit (6). A second stage (8) includes differentially coupled third (Q5) and fourth (Q6) input transistors and a load circuit (Q7,8). A first output (2A) of the first stage (4) is coupled to a first input of the second stage (8), a second output (2B) of the first stage (4) being coupled to a second input of the second stage (8). A common mode feedback amplifier (12) has an input coupled to receive a common mode signal (3) from the second stage (8) for producing an amplified common mode signal (9) on a control input of the controlled active load circuit (6) to provide fast settling of an output (Vout) of the second stage without substantially increasing amplifier noise.

An extended dynamic range optical amplifier, a method of operation, and a line amplifier configuration include an optical amplifier that can be optimized for high or low span loss conditions by switching an internal stage in or out of an internal light path within the amplifier. The extended dynamic range optical amplifier can include a low gain mode and a high gain mode with an internal switch to switch out a gain mid-stage in a low gain mode to extend the useful dynamic range of the amplifier. Further, the extended dynamic range optical amplifier can use residual pump power from an initial stage to pump the gain mid-stage in the high gain mode. Additionally, the extended dynamic range optical amplifier includes remapping of gain in the initial stage and the gain mid-stage to optimize the amplifier noise performance based on the maximum output power of the amplifier.

A lidar three-dimensional imaging system based on a virtual instrument comprises a three-dimensional scene modeling module, a lidar testing system simulation environment modeling module, a full-waveform signal processing module and a three-dimensional reconstruction module. The three-dimensional scene modeling module comprises a three-dimensional model loading element used for setting background colors, visual angle control, illumination, a projection mode, a display model and other basic scene projects. The lidar testing system simulation environment modeling module comprises four modeling sub-modules which are a laser pulse model, an atmospheric transmission model, an object interaction model and a receiving unit model. The laser pulse model is used for simulating a laser source according to the wavelength, pulse width, energy and other characteristics of a laser. The atmospheric transmission model is used for simulating a tested atmospheric environment, so that a noise model is generated for acting on the laser. The object interaction model is used for simulating effects of the laser and a detected object, and the effects comprise mirror reflection, diffuse reflection, surface reflection and speckles. The receiving unit model is used for simulating detector noise and amplifier noise which are generated after sensing.

The invention provides an optimization method of transmission performance of a long-distance coherent optical communication system for solving the problem of difficulty in quickly carrying out global optimization on the transmission performance of the coherent optical communication system with a long distance, a large cross-section number, unequal cross-section indexes and no dispersion compensation. The optimization method comprises the following steps that an optimal performance parameter of the whole optical communication link is computed based on link attention and amplifier noise characteristics; ranges and initial values of one group of weighting coefficients (m, t) are arranged; two factors including an optimal difference value of amplifier gain and an amplifier cross-section position are considered to arrange a module Mea (m, t, n), the corresponding Kminth amplifier cross-section position Mk is selected when the Mea is larger, the amplifier gain is Aopt, Mt, wherein k is equal to 1-Kmin, and the other amplifier gain is the initial value thereof. According to the optimization method, promotion of a light path performance index factor Q is considered, instantaneous characteristics, such as shake and time delay, which are caused by overlarge regulated quantity or overlarge regulation number, are avoided, and the performance of the optical transmission system is quickly optimized under the conditions of the extra-long distance and the large cross-section number.

Noise reduction for a switching amplifier system having a differential output stage and demodulator filter responsive to complementary PWM signals includes generating in-phase PWM signals and gradually adjusting their duty cycle between a low duty cycle and the full duty cycle of the complementary PWM signals, generating full duty cycle PWM signals and gradually shifting their relative phase between in-phase and out-of-phase; and in response to a turn-on signal, adjusting the in-phase PWM signals from low to full duty cycle and shifting the relative phase from in-phase to out-of-phase, and in response to a turn-off signal shifting the relative phase from out-of-phase to in-phase and adjusting the in-phase PWM signals from full to low duty cycle for maintaining balanced charge on the demodulation filter to reduce audible noise.

The noise figure of a low noise amplifier (LNA) is reduced without sacrificing performance such as gain, IIP3, and wideband impedance matching. Embodiments include configuring a control module of the LNA to sum and scale an output from a current-sensing branch of the LNA and an output from a voltage sensing branch of the LNA into one or more summed and scaled outputs. The control module also feeds the one or more summed and scaled outputs back to at least one of the outputs of the branches of the LNA.

A method for reproducing a low noise signal for a solid state imaging device which can reduce not only the reset noise but the amplifier noise around frequency zero, avoiding the saturation of the voltage conversion part in a bright scene, is accomplished by controlling a reset pulse of a CCD imaging device according to the result of comparing the output signal of the CCD imaging device with a reference signal value. When the output signal of the CCD imaging device is smaller than the reference signal value, the reset pulse is not applied to the CCD imaging device. Thereat, a pixel signal is reproduced as a differential signal between two signals sampled at two points with an interval of T0, the amplifier noise around frequency zero being reduced in the pixel signals.

A method of Raman detection for a portable, integrated spectrometer instrument includes directing Raman scattered photons by a sample to an avalanche photodiode (APD), the APD configured to generate an output signal responsive to the intensity of the Raman scattered photons incident thereon. The output signal of the APD is amplified and passed through a discriminator so as to reject at least one or more of amplifier noise and dark noise. A number of discrete output pulses within a set operational range of the discriminator is counted so as to determine a number of photons detected by the APD.

A pumping scheme for distributed Raman amplification (DRA) in optical fiber telecommunication systems is disclosed in which pump energy at the wavelength(s) required for DRA of the transmitted optical signal(s) is developed within the transmission fiber from a primary pump source through a series, n, where n >= 1, of Raman conversions resulting from the launch into the fiber of a primary pump source along with low-power seed sources. Alternatively, seed sources can be replaced by reflecting means to return, into the fiber, backward-travelling amplified spontaneous Raman scattered light resulting from high power in the fiber at a wavelength one Raman shift below the desired seed wavelength. The peak Raman gain thus occurs some distance from the primary pump launch terminal and leads to improved amplifier noise performance. Dynamic control of the magnitude and / or the spectral profile of the distributed Raman gain at, or near, a signal launch terminal can also be provided.

The invention discloses a noise suppression method for class D power amplifier, which includes a step S1 and a step S2; wherein, in step S1, an external enabling signal is received; in step S2, when the state of external enabling signal is changed, an enabling signal for a class D power amplifier is generated according to the external enabling signal; meanwhile, a silencing signal used for controlling the load of a class D power amplifier is generated according to the external enabling signal. The noise suppression method for class D power amplifier can effectively suppress POP or CLICK noisegenerated in capacitor charge-discharge process without increasing or modifying chip pins.

The invention discloses a method and a device for eliminating the noise of a balanced-unbalanced conversion amplifier. In an embodiment of the present invention, the output from the current sensing branch of the LNA and the output from the voltage sensing branch of the LNA are summed and scaled by using the control module of the LNA to generate one or more summed and combined Scaled output. The control module also feeds back the summed and scaled output to at least one of the outputs of the current sensing branch and the voltage sensing branch of the LNA.

Methods for design and production of highly sensitive active and passive light detecting devices and systems. Orders of magnitude improvement in optical signal detection is made possible in high noise or low contrast scenes. The current invention creates a small spectral difference between two parts of a split light stream. When recombined, the altered light streams partially correlate, and that generates fall amplitude signal oscillation at a frequency that depends on the constituent spectrum. The full amplitude signals and spectrum dependent oscillation make signal discrimination much better than intensity-only methods. The effect of read noise, amplifier noise, dark current noise, and thermal noise due to photo detector shunt resistance, become less important when compared to light detection using prior art methods.

The present invention relates to a method for optimizing performance of a multi-span optical fiber network. Each span has an associated optical transmission fiber connected to an associated optical amplifier. Gain and output power of the associated optical amplifier are respectively controlled independently. An amplifier noise figure respectively depends on the gain of the associated optical amplifier, with each associated optical amplifier further connected to launch optical signals into a remainder of a corresponding optical transmission line. The method includes the steps of for each span, computing the amplifier noise figure and a non-linear noise generated in the span based on information about the span and using the computed amplifier noise figure and the computed non-linear noise to compute an optimum launch power, and optimizing performance of the multi-span optical fiber network based on the computed optimum launch powers of all spans.