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This paper presents a quadrature direct digital frequency synthesizer (QDDFS) with super high memory compression ratio and analyzes its design principle theoretically. Its parameters have also been optimized. Trigonometric approximation and linear approach are combined coherently in order to reduce the size of the ROM (1856 bit). The compression ratio for(More)
To characterize the quality of wireless telecommunications system more efficiently and integrally, it is necessary to use error vector magnitude (EVM) to be the figure of merit. We give the definition of EVM and do some more improvement by describing a typical normalization. We also have simulated EVM for various distortion and various modulation types for(More)
Introduce the construction of wireless sensor networks on oil-drilling site. Build the framework of the system, configure the software and hardware, and analysis the process based on Zigbee technology. Realize the transplantation of TinyOS Operating system on the CC2430 Platform, data collecting, program debugging, and performance testing of wireless sensor(More)
This paper discusses the dependence of the phase error on the 50 GHz bandwidth oscilloscope’s sampling circuitry. We give the definition of the phase error as the difference between the impulse responses of the NTN (nose-to-nose) estimate and the true response of the sampling circuit. We develop a method to predict the NTN phase response arising from the(More)
This paper estimate the magnitude and phase response of a sampling oscilloscope (Agilent86100C with 50 GHz bandwidth) using the nose-to-nose method (NTN). The measurements are corrected for the non-ideal properties of the oscilloscope and calibration apparatus. In this paper, we present the first published repeatability study of magnitude and phase(More)
As the development trend of companies flattening the organizational structure, because of promotion space for employees getting smaller and increasing professional frustration, most people have different levels of sense of insecurity and having difficulty to control future. From the dimensions of job requirements and job resources, Job Demand-Resource model(More)
The relationship between parameter configurations of mechanical products are the main design rules that affect their work performance and the major factor that optimize product structure. However, the actual relationship of parameter configurations can't be gotten directly in the design specifications or the manual. Physical experimental methods are(More)
The virtual driving safety warning system is employed to remind the driver of dangerous operations in virtual driving, which can help to form good habit in real driving. The system can be divided into the hardware and software system. The hardware system is used for collecting, processing and transferring the driving operations from the driver. And the(More)
This article analyses the phase error on the 50 GHz bandwidth oscilloscope's sampling circuitry. We predict the nose-to-nose (NTN) phase response arising from the internal sampling circuitry of the oscilloscope and the phase error as which we definite is the difference between the impulse responses of the NTN estimate and the real response of the sampling(More)
Explicit and closed-form analytical expressions relating the spectral regrowth of the forward-link code division multiple access (CDMA) signal passed through a nonlinear amplifier to both the third-order intercept point and fifth-order intercept point, IP<sub>3</sub> and IP<sub>5</sub>, are derived based on a time domain model which is used to derive the(More)