tài liệu về lò vi sóng

Ngày tải lên: 20/01/2014, 07:20

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Ngày tải lên: 23/07/2014, 04:20

... of S 11 in (8.76) is always equal to 1. This is because in the vicinity of resonance, the parallel res- onator of Figure 8.11 behavior likes an open circuit. However, the phase response of S 11 changes ... of Kirchhoff’s two circuit laws and states that the algebraic sum of the currents leaving a node in a network is zero, with a driving or external current of i s the node equa- tions for the circuit of Figure ... resonator Y in = j ␻ C + = j ␻ 0 C ΂ – ΃ (8.74) Note that ␻ 0 = 1/͙L ෆ C ෆ is the resonant frequency. In the vicinity of resonance, say, ␻ = ␻ 0 + ⌬ ␻ , (8.74) may be simplified as Y in = j ␻ 0 C· (8.75) where...

Ngày tải lên: 15/12/2013, 06:15

... filter synthesis by optimization is a three-pole cross-cou- pled resonator filter having asymmetrical frequency selectivity. The desired filter response will exhibit a single finite frequency attenuation ... are violated. 9.3 OPTIMIZATION 287 minimize ⌬⌽,⌬⌰ Ή R b (⌽ + ⌬⌽, ⌬⌰) – R a (⌽)Ή where ⌬⌽ denotes the modifications to the physical design parameters for compensating the characteristic deviation ... the initial decomposition design, the filter is decomposed into individual cascaded sections, where reference planes of each individual section are represented by circuit nodes and the discontinuities...

Ngày tải lên: 15/12/2013, 06:15

... the improvement in selectivity over the Chebyshev filter is evident. The closer the atten- uation poles to the cut-off frequency (⍀ = 1), the sharper the filter skirt and the higher the selectivity. ⍀ a FBW ... rejection bandwidths are 100 MHz and 120 MHz, respectively, which obviously does not meet the rejection require- ments. Having determined the design parameters, the nest step is to find the physical ... communications systems, flat group delay of a bandpass fil- ter is demanded in addition to its selectivity. In order to achieve a flat group delay characteristic, two approaches are commonly used. The...

Ngày tải lên: 15/12/2013, 06:15

... even without the via hole grounding. Thus, it would seem that the voltage and current distributions would not change much in the vicinity of the midband fre- quency, even though the via holes are ... “New high temperature superconductive microstrip lines and resonators,” Applied Supercon- ductivity, Inst. Phys. Conf. Ser. 148, 1995, 1995, 1195–1198. [7] J S. Hong and M. J. Lancaster, “Novel ... is associated with the necessity of using low-value characteristic impedance lines ț High sensitivity to small variations in physical dimensions ț Excitation of higher-order modes ț Difficulty...

Ngày tải lên: 15/12/2013, 06:15

... stations vary but may focus on increasing sensitivity and selectivity: ț Sensitivity—The benefits of increasing sensitivity in rural areas is obvious since the number of mobile base stations and ... Nevertheless, the full-wave simulated re- sponse did verify the design approach. 12.3.3 Sensitivity Analysis Sensitivity analysis is very important for filter design, particularly for filter tuning, mainly ... specification. It is estimated the Q that can be attained is 50,000. Therefore, provided the required rejection and selectivity can be met, a filter with as low a number of poles as possible should be...

Ngày tải lên: 15/12/2013, 06:15

... the appendices. Chapter 2 provides an overview of wireless communication systems and their characteristics. 8 INTRODUCTION TABLE 1.4 Selected Applications of Microwave Solid-State Devices Devices Applications ... carry the video information as well. Table 1.1 shows the frequency bands used for commercial radio and television broadcasts. In the case of digital transmission, a standard monochrome television ... terrestrial communication system. Figures 1.3 and 1.4 list selected devices used at RF and microwave frequencies. Solid-state devices as well as vacuum tubes are used as active elements in RF and microwave...

Ngày tải lên: 15/12/2013, 11:15

... illustrated in Figure 2.7. A microwave signal generated by the oscillator is split into two parts via the power divider. The circulator feeds one part of this power to the antenna that illuminates a target ... Doppler frequency if the target is moving. Note that the signal travels twice over the same distance and, therefore, the Doppler frequency shift in this case will be twice that found via (2.4.33). Mathematically, o o  ... on-board electronics before transmitting it back. The gravitational force needs to be balanced somehow if this object is to stay in position. An orbital motion provides this balancing force. If a satellite...

Ngày tải lên: 15/12/2013, 11:15

... converted to corresponding impedance by moving to a point on the diametrically opposite side of the VSWR circle. It shows a normalized load impedance as 2  j2. Moving from this point by 3.15 l toward ... transformer is also presented along with a few examples to match resistive loads. Impedance measurement via the voltage standing wave ratio is then discussed. Finally, the Smith chart is introduced to ... Solutions to the transmission line equation are then constructed in order to understand the behavior of the propagating signal. This is followed by the concepts of sending end impedance, re¯ection...

Ngày tải lên: 15/12/2013, 11:15

... 3417,respectively. Substituting these into (4.5.5), Q of this cavity is found to be 2106. Circular Cylindrical Cavities Figure 4.20 shows the geometry of a circular cylindrical cavity of radius r and height h. It is ®lled ... CIRCUITS If the cavity is made of a perfect conductor and ®lled with a perfect dielectric then it will have in®nite Q. However,it is not possible in practice. In the case of cavity walls having a ®nite ... ac 3   m r e r r 4:5:2 Permittivity and permeability of the dielectric ®lling are given by e and m, respectively; o is angular frequency; and R s is the surface resistivity of walls which is related...

Ngày tải lên: 15/12/2013, 11:15

... re¯ection coef®cient of 0.2 is acceptable, circuits (iii) and (iv) can provide much wider bandwidth in comparison with those of the previous example. This concept can be used to shape the re¯ection coef®cient ... between them. This device can be inserted at a convenient point before the load. The impedance is matched by adjusting the lengths of the two stubs. Of course, it does not provide a universal solution. ... 36:6269 O ; C s  4:3453 pF and, X p  91:29009 O A C p  1:7434 pF Example 5.10: Reconsider the previous example where Y L  8 À j12 mS is to be matched with a 50-ohm line. Complete or verify the...

Ngày tải lên: 15/12/2013, 11:15

... characteristic impedance versus normalized length of the taper. This design can be achieved by moving the zeros at u Æ1 and Æ4 into the points Æ2 and Æ3, respectively. Hence, QuCu 2 À 2 2  2 u 2 À ... Hence, G in   L 0 dG in  1 2  L 0 e Àj2bz d dz ln  Zdz 6:7:3 Therefore, G in can be determined from (6.7.3) provided that  Zz is given. However, the synthesis problem is a bit complex because, in that case,  Zz ... meet such requirements. The chapter begins with the single-section impedance transformer that provides perfect matching at a single frequency. Matching bandwidth can be increased at the cost of...

Ngày tải lên: 15/12/2013, 11:15

... bằng các loại quả khô khác. Cách làm: - Rây bột. Tách lòng đỏ, lòng trắng trứng. - Đánh lòng trứng cho đến khi nổi. Thêm đờng, đánh tiếp. - Thêm lòng đỏ, đánh đến khi nổi cứng. - Thêm bột, đánh nhanh ... đĩa thoa mỡ đờng kính 28 cm. Quét dầu lên bánh, phun nớc. - Đậy nắp bằng tấm bao dùng trong lò vi sóng. Nhấn Steam menu 3 lần để Dumpling-hấp. - Lặp lại cho đến khi hết bột. Mixed ingredents...

Ngày tải lên: 23/12/2013, 05:17

... sợi, nấu 3, High. Sau đó cho thêm bột ngô pha loÃng với nớc, khuấy đều. Nấu không đậy nắp trong lò 50. - Dội sốt lên bông cải, dùng nóng. Chicken rice pot Cơm gà Thành phần: - 300g thịt gà ... loại xong, bỏ nớc luộc đi. - Ngâm khoai vào nớc sôi, lột bỏ vỏ. - Xếp rau vào bát hoặc đĩa sâu lòng. - 2 2/3 thìa canh nớc chanh tơi. - 1 thìa canh mùi tây cắt nhỏ. - 1/4 tbs muối. - Một nhúm ... bơ vào khay hoặc nồi hình chữa nhật, vuông 25cm. Nấu 1 2, chế độ High cho tan. Trộn tất cả vật liệu vào bơ, trừ cá. - Lăn cá vào sốt bơ cho đều các mặt, xếp trong khay, đậy bằng tấm plastic. Nấu...

Ngày tải lên: 23/12/2013, 05:17

Ngày tải lên: 23/12/2013, 05:17