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射频通信电路第二版答案.pdf

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第01章.pdf
第02章.pdf
第03章.pdf
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第06章.pdf
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第10章.pdf
−= dB16 = .0 158 = H53.4 μ 10 12 − 1 × 2 7 ) 56 = 67.66 × = .0 124 −= dB13.18 1 26.0 × 10 × 67.66 2 ⎞ ⎟ ⎠ ⎛ ⎜ ⎝ 第一章 1-1 =S f = f 0 ± 100 将 得 1-2 (1) 1 26.0(1 × + 10 640 0 =f × 2 )67.66 代入 kHz f 0 Q = 640 200 = 32 kHz 及 kHz Q=20 BW = dB3 S = 1 + L = Q 0 = 1 C ω 2 0 f 0 BW 1 = dB3 2( 10 × π 10 15.0 = 0 Q ⎛ ⎜⎜ ⎝ 300 = (2 f 0 f − f 0 时 = kHz f 0 BW dB3 = 2 ) ⎞ ⎟⎟ ⎠ 1 + 10 3.0 = 33.33 (2)当 BW dB3 = Qe = 回路谐振电导 G 1 Q ρ 回路空载谐振电导 1 Q ρ G = 0 e 并联电导 并联电阻 1-3 L 1 = 1 ) 2( 2 f π 1 C 1 1 Cf ( ) π 2 2 1 ) f π C 2 2 3 3 2( L 2 = L 3 = H06.2 μ = = . 742 H μ 2 = H68.0 μ = ω 0 Q C e = 2 π × 10 × 10 12 − 56 × 7 33.33 = 55.10 × 10 − 5 (s) e = ω 0 Q C 0 0 = 2 π × 10 × 10 12 − 56 × 7 67.66 = 27.5 × 10 − 5 (s) GGG − = e 0 55.10( − )27.5 R = 1 G = 28.5 = − 5 10 K9.18 Ω = 1 × 10 × 5 − = 28.5 × 10 5 − (s) L2 C2 L3 C3 v1 v3 C1 L1 2 2’ 1-4 x x f0 f f0 f
(a) f 0 = 1 π2 LC (b) f 0 = 1 π2 LC (c) f 1 = 2 π f 2 = 1 LC ( 1 1 CL 1 2 π + L 2 ) (d) f 1 = f 2 = π 2 2 1 LC 1 CC 1 2 C C + 1 2 2 π L 1-5 由于回路为高 Q,所以回路谐振频率 = ≈ 1 f 0 1 12 − π LC 2 2 π 300 × 10 × 390 回路的损耗电阻 = 465 5. kHz − 6 × 10
Ω ) 6 − × × 0 r × = = r = + = L Ω 1( 5. 10 390 465 3 10 100 2 × π RP 2 0Q 4.11 K114 ω 0 Q 回路的谐振阻抗 = 考虑信号源内阻及负载后回路的总谐振阻抗为 R S 回路的有载 Q 值为 R × 3 10 42 = Σ Lf πρ 2 0 5. 465 37 处的选择性为: 通频带 10=Δf f 0 eQ 56.12 kHz K42 Qe kHz BW =Σ 37 dB3 Ω = = R R R = = = = || P || L 在 1-6 回路特性阻抗 回路谐振阻抗 由 + = 2 P 2 R L 1 R P 2 P 1 R S S = = 1 1 + Q e ⎛ ⎜⎜ ⎝ f 2 Δ f 0 2 ⎞ ⎟⎟ ⎠ 1 1 + ⎛ ⎜ ⎝ 37 × 2 20 5.465 ⎞ ⎟ ⎠ = .0 532 −→ dB47.5 7 1 × 100 k9.15 Ω 10 = = 159 Ω − 12 10 × π × 2 100 × = ρ = 1 Cf π 2 0 RP ρ Q 159 = = 可求得 2 =P 336.0 R S 2 P 1 = = .0( 8.12 2 )8.0( 1 336 ) 2 = k20 Ω = k86.8 Ω R ' L = R L 2 P 2 1 86.8 = .0 0629 + 05.0 + 112.0 = .0 226 ms 信号源内阻 SR 折合到回路两端为: R ' S = 负载电阻 LR 折合到回路两端为: 回路总谐振阻抗 ΣR 为 1 1 ' ' R R S L 即 k43.4 =Σ Ω 回路有载 Q 值为 1 9.15 1 20 43.4 1 R 1 R P R + = + + = = Σ + Qe R = Σ ρ 回路的通频常 BW dB3 = f 0 eQ 3 10 × 159 10 10 × 8.27 = = 8.27 6 = .0 359 MHz 1-7 由于 BW = dB3 f 0 eQ 所以回路有载 Qe = f 0 BW dB3 = 6 10 × 10 20 = 50 3 回路谐振时的总电导为 = ω eLQ 回路的空载电导为 G = 1 Σ 0 × π 2 1 159 6 10 × − 6 × 10 × 50 = .020 ms (即 R =Σ 50 K )Ω
= G p ω 0 1 LQ 0 = .010 ms (即 RP 100= K ) 信号源内阻折合到回路两端的电导值为 由于 G ' S ,所以电容接入系数为: GG 010= = Σ =⇒ GP 01.0 ms ' = S G − P P = = ' S . p − 3 2 S 2 1.0 01.0 10 × 3 − 10 S L = 1 26 ) 28.6( × 10 × 159 × 10 − 6 = 159 PF 回路总电容 C ∵接入系数 P = = = G G 1 2 ω 0 1 C ω 1 C ω =C 2 1 1 − CP = C 1 ,所以 1-8 + 因此回路的总电容为 + C C C C = 2 2 ' =Σ i = C C 2 所示 C = 2 = 1590 PF C P 159 9.0 = 176 PF C 0 = PF40 CC ' 1 C C 1 ⋅ + += 5 2 ' 2 20 20 × + 40 40 = PF3.18 回路谐振频率 ω 0 = 1 ΣLC = 1 × 8.0 × 10 − 6 3.18 × 10 12 − = 26 × 10 7 rad/s 回路的空载谐振阻抗为 Q ωρ 0 RP = = 0 0 电阻 0R 对回路的接入系数为 C 1 考虑了 iR 与 0R 后的谐振阻抗 ΣR 为 P = = 26 × LQ 7 10 C 1 C + × 8.0 = '2 1 R Σ = 1 R P + 1 R i + P R 2 0 = 1 9.20 + 1 10 + 6 − × 100 = k9.20 Ω = 17.0 ms(5.9k Ω ) 10 × 1 3 2 ) 1( 3 5 回路有载品质因数为 = = Qe R Σ ωρ 0 BW ω eQ = dB 0 3 1 17.0 × × 26 28 L = 10 7 × 10 ≈ 28 − 3 回路通频常 = . 930 7 × 10 rad/s = 1.48MHz 1-9 设回路的空载 ∞=0Q ,设 P 为电容接入系数 率传输, P = C 1 C + 2 C 1 ,由于有最大功
可得: L = R S =→= P .0 333 R P L 2 BW dB3 =→= 10 e Q f 0 Q → e Qe = Σ = R Σ L 0ω R eQ ω 0 CC ⋅ 2 C C + C Σ P PF33 = 1 1 = = C Σ C 2 1 =C 5.4 16 2 π × 1 ω 2 0 = L 2 22 333.0 = 2( × π = PF66 R =Σ R S || R L 2P = k5.4 Ω × × 10 10 3 6 × 10 = H48.4 μ 1 ) 2 16 × 10 6 × 48.4 × 10 − 6 = PF22 ∴ ∵ ∵ 1-10 由 C =Σ BW dB3 =→= Q e f 0 Q e R X i f 0 BW dB3 50 40 = 25 9 10 = 40 , 6 10 × ∵ e = → =ΣCX Q ,由 2R 与 2C 组成的并联支路 Q 大于 4 以上,则 25.1 = C Σ 2 >>Q , 1 25.1 2
x 2 = < = 10 20 Ω LX ⋅= Qr =× 当 Q=2 时要求与 r=10 串联的电抗值为 8.62 Ω 因此在匹配网络中采用电容 1C 的容抗与 0.1μH 的电抗部分抵消,见 图示。 =→Ω PF2.37 0.1μH =− 8.62 8.42 10Ω 20 C2 C1 C X X = = − = x C 1 L 由于 Q = 50 X C 2 → X C 2 =→Ω= 25 C 2 25 × 1 28.42 × π 8 10 × PF7.63 = 10 8 1 1 2 π × 1-16 (a) Vi = , I 4= , I i V Ri = V 则 VL R R (b) 由图(b): V + 1 4= , I I L = , V I V = 1 1 I i = , 1 16 I = , 2 2V , 1I , 2I Vi Z = = = C L 2 i RL 1 4 2V = 则 I L = , 22I 2V VL = , R R 16 1 = i L V I 4 V 4 = I R L 2 Ri = V 2 4I 1 V 24 I 1 RL = I1 I1 V1 I2 V2 RL V1 V2 I2 (b)
= 1 2 R i = 8 R L = 2 R L Z C 1 Z C 2 = = V 1 I 1 V 2 I V 2 I V I 2 Ri = , RL = , V I 2 R R L i = Z C = 2= R L Vi R R i L Z C = V 3= 9 1 V I = I VL = , I i = , V 3= R L Ri V V 4 1 RL 2 RL 2 I L 3= I Ri (c) I V V I I RL I (d) V = 3 3V 1 I I = , 3 V I RL I = , 2 I 1 Ri = , Ri , R 3 V 1 3I 1 9 Z Z C = = = C 1 1 2 Z C 3 = 3 = V I 3 V 3 1 I 1 3 3 = V = , 1 V 2 V 3 1 I 1 V 1 I = = R 1 2 L = 1 3 R L Ri V1 V2 V3 I3 I3 RL I1 I1 I2 I2 (e) (c) (d) (e) 则
第二章 2-1 10 -23 × 290 × 510 × 10 3 × 10 5 = 16.8 × 10 10 − )V( 2 2 =nV kTR4 1 =nI 2 4B kT4 = × B 1.38 ×= 1 R 1 250 510 × 250 510 + kTRB 68.2 = = 1 RR || 2 2 =nV 4 3.14 × 10 21- )A( 2 = 167 k7. Ω × 10 10 − )V( 2 2-2 则 由于匹配,所以输出额定噪声功率 kTB=nP 2-4 先把 dB 数化为自然数 G=15dB=31.62;NF=2dB=2; T +=→ 800 = k 1 F 2 2 e 2 += 1 T e T 0 800 290 = . 763 放大器的等效噪声温度为 F = ( Te 1 − T )1 0 = )12( ×− 290 = 290 k 系统的等效噪声温度为 T e = T e 1 + 系统的噪声系数为 FF 1 = + T e 2 G = 290 + 800 62.31 = k3.315 1 F − 2 G += 2 1 76.3 − 62.31 = .2 087 2-5 噪声底数为 −=tF −= 174 174 dBm/Hz 10 ++ 3 + log NF(dB) 10logB + 10 121 dBm −= 5 放大器的线性动态范围可以定义为它的 1dB 压缩点的输入功率与噪声底数之比,即 若 −=lDR dB SNR ( 则灵敏度 dBm dB 111 F = t )121( P in SNR o ,) ( 20=min 101−= 10 min min + = − ) o , , −=lDR 放大器的线性动态范围也可以定义为它的 1dB 压缩点的输入功率与灵敏度之比, 则线性动态范围为 ( 101 dB 10 91 = − )
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