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types of pressure sensors

时间:2021-06-14 01:54:19 来源:网络整理编辑:HMS Networks

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A secure server similarly needs to be protected against physical threats. These threats include physical removal from its operating environment, or disassembly to modify internal components, for example by replacing the internal hard drive or BIOS boot ROM. Therefore, a secure server requires specialized mechanical packaging modeled after a cryptographic HSM making it difficult, or impossible, to probe, disassemble, or modify components within the enclosure. The Federal Information Processing Standard (FIPS 140), used to measure the security of specialized cryptographic processing machines, can be used as a guide for the physical security design of a more general secure server machine.

A secure server similarly needs to be protected against physical threats. These threats include physical removal from its operating environment, or disassembly to modify internal components, for example by replacing the internal hard drive or BIOS boot ROM. Therefore, a secure server requires specialized mechanical packaging modeled after a cryptographic HSM making it difficult, or impossible, to probe, disassemble, or modify components within the enclosure. The Federal Information Processing Standard (FIPS 140), used to measure the security of specialized cryptographic processing machines, can be used as a guide for the physical security design of a more general secure server machine.

where N is the order and R is the down-sampling rate. We have used N=5 and R=32 for the EDGE IF stage. For high values of R, this expression approximates the multiplication of 2N sinc functions, resulting in very low sidebands and deep nulls.

An FIR filter is used for the compensation filter, simulated with 32, 16, 14, 12, 10, and 8 bits to assess the distortions introduced. This filter is a low-pass windowed (Hamming) filter with the frequency response shown in Figure 4 . The different traces are frequency responses for different bit widths, with the overall performance determined by the number of bits chosen. The choice of any of these representations requires the designer to do a trade-off analysis in order to come up with the most economical solution without jeopardizing the performance of the phone.

types of pressure sensors

Figure 4:  Frequency response of the EDGE compensation FIR filter for different word lengths

types of pressure sensors

To determine the performance margins of the receiver design, the error boundaries should be established through simulation. These results are then augmented by the addition of real world” margins, which are obtained by prototyping and testing in the design-verification stage. Receiver error sources may be the result of many factors, including:

This list clearly shows that the source of these errors could be in the RF, baseband, or analog portion, but we are particularly interested in quantifying the distortions due to fixed-point effects.

types of pressure sensors

Standard performance verification tests are incorporated into most digital communications standards. 3GPP and EDGE both have procedures and specifications for the in-channel and off-channel tests.

One key performance specification for a receiver is sensitivity, which is generally specified at a particular BER. Sensitivity is defined as the median level of the received signal that produces a specified BER when the signal is modulated with a specified pseudo-random binary sequence (PRBS) of data.

When light is normally incident on the structure, the transmitted portion of the light-that which passes through the grating structure-is affected. The effect on the passed light can be varied by adjusting the size, shape and spacing of the grating structure. In particular, for the one-dimensional grating structure in Fig. 1, appropriate selection of dimensions will result in behavior as a polarizer, waveplate or polarization-dependent filter. More sophisticated effects, such as polarization-independent filters, can be achieved by two-dimensional gratings, as shown in Figure 2 . The general class of these structures is referred to as SOEs.

Because the diameter of the incident light beam is often much larger than the structures of the grating, the effect on the transmitted light is really the statistical sum of numerous local interactions between the light and the grating. For example, if a light beam measuring 300 microns in diameter is incident on a two-dimensional grating such as that shown (Figure 2 again), where the structure size is roughly 100 x 100 nanometers, more than a million nanostructures will be illuminated. Therefore, varying the grating dimensions spatially across the incident beam front allows additional control over optical-processing effects.

The physics of the SOE depends on rigorous application of the boundary conditions of Maxwell's equations to describe the interaction of light with the structures. At the wavelengths of light used in telecommunications-980 through 1,800 nm-the structures required to achieve those effects have some dimensions on the order of tens to a few hundred nanometers. At the lower end of the scale, single-electron or quantum effects may also be observed.