Nec Corporation

Sony Corporation

Other

Shigeji Ikeda

Atsuhiro Kumagai

Kiyoshi Yonishi

Akihiko Sugiyama

Shinichi Fukuda

Tetsu Taguchi

Toshihiko Sato

Isao Ohdaira

Embodiments of the invention provide a battery pack including a pack body and a plurality of terminals. The pack body has first and second main surfaces that are opposed to each other in a first axis direction, first and second end surfaces that are opposed to each other in a second axis direction orthogonal to the first axis direction, and first and second side surfaces that are opposed to each other in a third axis direction orthogonal to the first axis direction and the second axis direction. The plurality of terminals includes a positive terminal, a negative terminal, a temperature detection terminal, and a control terminal that are arranged on the first end surface along the third axis direction. The negative terminal is arranged between the temperature detection terminal and the control terminal and closer to the control terminal than the temperature detection terminal.

Battery pack

A memory space of a memory cell array is divided into a plurality of submemory spaces. A refresh control circuit executes a control of performing refreshment of information to the submemory spaces that are in use at the time of the refreshment of the information and need the refreshment among the plurality of submemory spaces and executes a control of not performing the refreshment to the submemory spaces that are not in use and do not need the refreshment.

Memory device, refresh control circuit to be used for the memory device, and refresh method

A signal-to-noise power ratio estimation circuit,detects an error signal power of an error signal output from a subtracter,and a pseudo noise signal power of a pseudo signal output from an adaptive filter,and, based on the detected signal powers, outputs an estimated value SNR1 of a signal-to-noise power ratio. An SNR average circuit,calculates an average value SNR4 of the SNR1. A step size output circuit,controls the step size of the adaptive filter,according to the SNR4 value.

Noise cancelling method and noise cancelling unit

A noise canceler of the present invention is of the type including an adaptive filter for generating a pseudo noise signal, subtracting the pseudo noise signal from a received signal to thereby output an error signal, and sequentially correcting the filter coefficient of the filter in accordance with the error signal. A second adaptive filter produces a second pseudo noise signal and a second error signal. A first and a second power mean circuit each calculates the signal power of the respective signal. A divider performs division with the resulting two kinds of signal power, so that a signal-to-noise power ratio is estimated. A comparator compares the estimated signal-to-noise power ratio and a delayed version of the same and outputs greater one of them as an extended signal-to-noise power ratio. A step size output circuit corrects, based on the extended signal-to-noise power ratio and reference noise signal power output from a power mean circuit, a step size used to adaptively vary the filter coefficient of the first adaptive filter.

Noise canceling method and apparatus for the same

An object of this invention is to provide an adaptive filter capable of reducing a convergence time and residual error even when there exists an interval having a small input signal power for a long time, and an adapting method thereof. The adaptive filter comprises a signal power monitoring circuit for receiving an input signal and outputs of delay elements and outputting a first stop signal for stopping tap position control and a second stop signal for stopping coefficient updating and a coefficient updating control circuit for receiving the second stop signal and an error signal outputted by a subtracter and outputting the error signal or zero to coefficient generating circuits as an updating signal. The signal power monitoring circuit calculates a sum of powers of all or part of signals of the delay elements, so that if the power sum is smaller than a first threshold, it turns on the first stop signal to stop the tap position control and if the sum is smaller than a second threshold, turns on the second signal to stop the coefficient updating.

Adaptive filter and adapting method thereof

A noise canceler of the present invention includes a signal-to-noise power ratio estimator to which a main signal and a reference signal are input. The estimator 10 estimates the sinal-to-noise power ratio of the main signal from the mean power of a desired signal contained in the main siganl and a mean power of a noise signal also contained in the main signal. In addition, the estimator estimates the signal-to-noise power ratio of the reference signal from the mean power of a desired signal contained in the reference signal and the mean power of a noise singal also contained in the reference signal. An adptive filter for estimating the noise signal of the main signal has its step size for coefficient updating controlled in accordance with the estimated signal-to-noise power ratio of the noise signal. On the other hand, an adptive filter for estimating the desired signal of the reference signal has its step size for coefficient updating controlled in accordance with the estimated signal-to-noise power ratio of the reference signal. Delay circuits are provided for compensating for a delay ascribable to a power averaging procedure which a signal-to-noise power ratio estimator executes to calculate the estimated siganl-to-noise power ratios.

Noise canceler

In accordance with the present invention, for noise cancellation, a reference noise signal is input to signal-to-noise (SN) power ratio estimating circuitry via a reference signal input terminal. The SN power ratio estimating circuitry causes its adaptive filter for producing a pseudonoise signal from the reference noise signal to operate. The circuitry detects error signal power and pseudonoise signal power out of the pseudonoise signal and other signals, and then outputs an estimate of an SN power ratio based on the detected power. A first delay circuit is connected to the output terminal of the above circuitry. A comparator compares an estimate of an input to and an estimate of an output from the first delay circuit, and produces greater one of the two estimates as an expanded estimate. A step size output circuit controls, based on the expanded estimate, the step size of a second adaptive filter connected to the reference signal input terminal via a second delay circuit. A subtracter subtracts a pseudonoise signal output from the second adaptive filter from a received signal sequentially delayed by a third and a fourth delay circuit, thereby cancelling a background noise signal component contained in the received signal.

Noise canceling method and apparatus therefor

An input signal is supplied to a tapped-delay line adaptive filter to produce tap signals which are equally divided into groups. The tap signals are selectively coupled on a per group basis through a switch to coefficient generators where tap-weight coefficients are produced. The selected tap signals are weighted respectively by the coefficients and summed together to produce a correction signal, which is combined with an output signal which is a replica of the input signal. The coefficients are updated with a residual error of the correction signal. Using the coefficients, the hopping order for selecting a tap group and the dwell time of the tap group are determined. Total power of the selected tap signals is monitored. When the monitored power is lower than a threshold value, the determination of the hopping order and dwell time is disabled, coefficient updating is disabled, and the residual error is nullified for fast convergence.

Adaptive filter with disabling circuit for fast tap weight convergence

The object of the present invention is to provide a noise cancelling method and a noise canceller where the shortening of the convergence time and the reduction in the distortion (residual error) after the convergence can be realized. A second adaptive filter outputs a pseudo noise signal by receiving a reference signal from a reference signal input terminal. A subtracter subtracts an output pseudo noise signal of the second adaptive filter from a receiving signal input from a speech signal input terminal, and supplies the subtraction result to the second adaptive filter as an error signal. A divisor circuit divides an output speech signal power of a power averaging circuit obtained from the output error signal of the subtracter by an output noise signal power of another power averaging circuit obtained from the output pseudo noise signal of the second adaptive filter, and outputs the result of the division as an estimated value of the signal to noise ratio (SNR). A step size output circuit operates so as to receive the output signal of a signal to noise ratio estimating circuit as an input, and output a value corresponding to the input SNR value as the step size for a first adaptive filter.

Noise cancelling method and noise canceller with variable step size

In a noise cancelling device including a first subtractor (5) for producing a first difference signal as a noise cancelled signal by subtracting a first pseudo signal from an input signal having a main signal and a first noise signal superposed on the main signal and a first adaptive filter (4) for processing a second noise signal correlated with the first noise signal into the first pseudo signal in accordance with filter coefficients thereof, a second subtractor (7) subtracts a second pseudo signal from the first pseudo signal to produce a second difference signal. A second adaptive filter (6) processes the second noise signal into the second pseudo signal in accordance with filter coefficients thereof. First and second power averaging circuits (8 and 9) produce first and second averages (P1 and P2) of power of the second difference signal and the first pseudo signal, respectively. A step size calculating circuit (10) calculates, from the first and the second averages, a step size for use in renewal of the filter coefficients of each adaptive filter in deciding a rate of convergence of each adaptive filter at a time. The first adaptive filter renews the filter coefficients thereof into renewed filter coefficients in accordance with the second noise signal, the first difference signal, and the step size. The second adaptive filter renews the filter coefficients thereof into renewed filter coefficients in accordance with the second noise signal, the second difference signal, and the step size.

Noise cancelling device capable of achieving a reduced convergence time

In an adaptive filter, each of first through N-th taps belongs to either one of first through M-th tap groups. A first generating section (31) generates a specific one of the first through the M-th tap groups. A second generating section (32 to 34, 37, 38) generates a tap select signal in accordance with first through K-th tap gains and the specific tap group, where a positive integer K is less than a positive integer N. By the tap select signal, a tap select section (22) connects first through K-th selected taps to a filter section (20-1 to 20-(N-1), to 24-1 to 24-K, 25-1 to 25-K, 26, 27). A control section (40, 41, 52, 53) is responsive to the tap select signal for controlling the first generating section to make the first generating section generate a renewal one of the first through the M-th tap groups as the specific tap group.

Growing community of inventors

Tokyo, Japan

Shigeji Ikeda