In this letter, it is clarified that the quantum noise properties of the linear amplification and locking amplification in the injection locked laser process are different. The noise property of the locking amplification is newly given.

It often occurs in the acoustic environment that a specific signal is contaminated by the additional noise of non-Gaussian distribution type. In order to extract exactly the various statistical information of only specific signal from the observed noisy data, a stochastic signal processing by use of digital computer is essential. In this study, a stochastic method for estimating the probability function of the specific signal embedded in the additional noise is first theoretically proposed in a suitable form for the quantized level observation. Then, the effectiveness of the proposed method is experimentally confirmed by applying it to the observed data in the acoustic environment.

In this paper, we analyze a photodetection process of new kind theoretically, which transforms a coherent state of light so as to lead to nonstandard property, namely, sub-Poissonian distribution of its output photoelectron during its photodetection process. The properties of the photoelectron distribution are studied used as preamplifiers of both direct-detection and homodyne detection cases.

A ner trial of statistical evaluation for a nonstationary traffic flow and its traffic noise is proposed as a prediction method of its probability distribution function by considering the temporal change of distribution parameters especially from a structural viewpoint. First, a headway distribution of the nonstationary traffic flow passing through within a road segment is proposed on the basis of an Erlang distribution by reflecting a temporal change of its distribution parameters. Then, an initial phase density concerning with asynchronous counting method and the probability of counting n cars over a long time interval are derived from the above nonstationary expression of headway distribution. Thus, the statistics of noise intensity at an observation point has been predicted by combining the above probabilistic factors and deterministic factors related to noise propagation environment with use of a compound stochastic process model. Finally, te effectivenss of the proposed theory has been confirmed experimentally by applying it to the actual traffic flow on a highway.

Noise characteristics of InAlAs/InGaAs HEMT's passivated by SiN are investigated to ascertain their suitability for practical applications in circuit such as MMIC's. A 0.18-µm-gate-length device with 125-µm-gate width and 8-gate fingers showed the lowest minimum noise figure of 0.43 dB at 26 GHz with an associated gain of 8.5 dB of any passivated device ever reported. This value is also comparable to the lowest reported minimum noise figure obtained by bare InAlAs/InGaAs HEMT's in spite of increased parasitic capacitances due to the SiN passivation. Thes excellent noise performance was achieved by employing non-alloyed ohmic contact, a T-shaped gate geometry and a multi-finger gate pattern. To reduce the contact resistance of the non-alloyed ohmic contact, a novel n+-InGaAs/n+-InAlAs cap layer was used resulting in a very low contact resistance of 0.09 Ωmm and a low sheet resistance for all layers of 145 Ω/sq. No increase in these resistances was observed after SiN passivation, and a very low source resistance of 0.16 Ωmm was obtained. An analysis of equivalent circuit parameters revealed that the T-shaped gate and multi-finger gate pattern drastically decrease gate resistance.

The optimal coding strategy for signal detection in the correlated gaussian noise is established for the distributed sensors system with essentially zero transmission rate constraint. Specifically, we are able to obtain the same performance as in the situation of no restriction on rate from each sensor terminal to the fusion center. This simple result contrasts with the previous ad hoc studies containing many unnatural assumptions such as the independence of noises contaminating received signal at each sensor. For the design of optimal coder, we can use the classical Levinson-Wiggins-Robinson fast algorithm for block Toeplitz matrix to evaluate the necessary weight vector for the maximum-likelihood detection.

This paper analyzes the performance of the capacity controlled digital radio system, which controls the number of modulation levels according to the amount of traffic. These analyses are performed under thermal noise and co-channel interference. As a result, the throughput improvement is approximately 16 times comparing with the fixed capacity system which has the designed outage probability of 0.1%. Theoretical results are applied to the future mobile communication system which utilizes TDMA access method or burst co-dec, and it is found that the reuse distance can be improved to 1/5 times when the designed outage probability is 0.1%.

Design consideration, fabrication process, and performance of a fully monolithic 22 GHz-band oscillator implemented using a self-aligned AlGaAs/GaAs heterojunction bipolar transistor (HBT) are described. For optimization of the oscillator circuit parameters, large-signal circuit model parameters extracted from bias dependent small-signal S-parameters have been used to maximumize an output power. The developed oscillator employs a 1.510 µm2 emitter AlGaAs/GaAs HBT fabricated by using a dual sidewall self-aligned process. The fabricated oscillator has exhibited an output power of 6.2 dBm at 22.16 GHz with a collector efficiency of 9.5%, and phase noise of 78 dBc/Hz at 100 kHz off-carrier under free-running condition. These results were in good agreement with the large-signal designed results obtained using harmonic balance simulator.

A new error rate formula for narrowband Differential Quaternary Phase Shift Keyed system in a Rayleigh fading channel is obtained in closed-form. The formula predicts a non-zero error probability for noiseless reception. As predicted, the computed error rates approach some constant or floor values as the signal-to-noise ratio is increased beyond a certain limit. In the presence of various Doppler frequency shifts, an IF filter bandwidth of about one times the symbol rate is found to lead to a minimum error probability prior to the appearence of the error rate floor.

A new approach is proposed to evaluate total electromagnetic noise radiated from a printed circuit board (PCB), and a result of experimental verification is given. The purpose is to represent the total radiation noise by summing up noises from elemental sources on a PCB, such as signal traces or ICs. Each of the elemental noise is calculated by an a priori noise model for each component of a PCB. Parameters of each noise model should be determined experimentally. Radiation sources on a digital PCB were found to be not only signal traces between ICs, but also package-side loops each of which is composed of an IC and a decoupling capacitor. Radiation noises from these two kinds of sources were evaluated separately. Experimental PCBs, which are two-layer PCBs mounting a few high-speed CMOS (HC) ICs, were prepared and radiation power from them was measured. Each PCB has a ground plane on one side, which simulates an internal ground plane in a multilayer PCB, and signal traces on it have a configuration of a microstrip transmission line. Electromagnetic noise caused by a high-speed CMOS gate is radiated impulsively during transition time as short as about 10ns. No significant interference was found between the noises from separate traces because each of the noise is impulsive and rarely overlaps each other. It is concluded that the total radiated power is represented by a simple sum of radiations from each traces without any interference to be taken into account.

A random pulse stream (RPS) generator was developed for the noise immunity test of various digital system including communication system. By using this RPS generator along with the composite noise generator (CNG) developed formerly, the Middleton's "Class A" noise could be generated, and the total system (RPS+CNG) became more general noise simulator. In this paper, the configuration of CNG with newly developed RPS generator, and a typical example of Class A noise generated by this system are shown.

A layout system for mixed analog/digital standard cell LSI's is described. The system includes interactive floorplan and placement features and automatic global and channel router. In mixed analog/digital circuits, crosstalk noise causes chip performance degradation. Thus, the proposed global routing algorithm routes analog nets in areas that are free of digital nets as much as possible. The number of line crossovers, especially for analog nets, is minimized by both global and detailed routers, because these crossovers are the dominant factors in the crosstalk noise. Double width lines can be used to avoid unexpected voltage drops caused by parasitic resistances. A postprocess automatically puts up shield lines for very noise sensitive wirings to improve the S/N ratio. Experimental results show that the proposed algorithms are effective in reducing the number of crossovers and redundant vias.

We propose a new distributed signal (analog or digital) transmission system which has the immunity against the noisy channel. An information signal in transmitter is distributed by distributor and the distributed signal is transmitted. Received signal is reconstructed by the inverse distributor in receiver. In this system, an impulsive interference noise which disturbs the transmission signal in the channel passes decoder only, and this interference noise is distributed by the inverse distributor while the transmitted signal is reconstructed. Some appended signals make it possible to estimate the noise components which inversely distributed with the Fourier transformation as the distributor. Basing upon this principle, the transmission system will have an ability to suppress the impulsive interference, and the channel will have high noise immunity. The construction of receiver which can eliminate the impulsive noise is derived.

This paper outlines an approach for specifying emissions performance at the component level. The objective is to move towards an industry specification for radiated emissions from large integrated circuits in order to facilitate cost effective system design for EMI compliance. Simple models of the mechanisms of direct chip radiation are provided based on the physical and electrical structure of large integrated circuits. These models lead to simple algorithms for estimating the total IC radiation based on IC design parameters. These models can be related to proposed emissions limits based on the desired application of the IC. Finally a measurement methodology is described which permits evaluation of the IC's relative to the limits and provides the information required to make detailed simulation models.

Electromagnetic interference on a bus wiring configuration of the ISDN basic interface using metallic telecommunication lines is studied. A simple circuit to simulate terminal equipment unbalance about earth is developed for measurement purposes, based on the fact that the unbalance weakens the withstanding capability against interference. The electromagnetic interferences from low-voltage supply lines, analog telephone lines and broadcasting waves are evaluated by experiments using the circuit. The interference is measured by both induced voltage on the interface line and the error rate of the transmission signal line. Consequently, it is clarified that the basic interface is disturbed by the induced voltage, because the terminal equipment in the CCITT Recommendation I.430 has too large an unbalance about earth to maintain transmission quality. Adding to this, countermeasures to reduce interference are proposed.

In this paper, we present a new image compression scheme, Projection-VQ, based on reconstruction from vector quantized projections. We can easily deal with the blocks of larger size in Projection-VQ than in conventional VQ schemes, because the dimension of vectors in projection domain is, in general, much smaller than that in the spatial domain. In Projection-VQ, the image can be reconstructed without destroying edge sharpness in the process since the projection data having the edge information are preferentially transmitted. There are several good algorithms of reconstructing an image from projections. However, we use a new modified reconstruction algorithm suitable for a variable bit rate image coding system. We allocate the bits depending on the characteristics of the block images. Our simulation results show that the performances are superior to the ordinary VQ schemes in PSNR, and that the improvement in subjective image quality is substantial.