本文主要讨论如何减小已调幅波通过 LC 电路后产生的解调失真及一些有关的问题。一、包络畸变的分析单一频率调制的已调幅波包含载频、上边频、下边频三个频率分量,它可以写成v_i=V_i[1+mcosΩt]cosω_ct=V_i cosω_ct+(m/2)V_icos(ω_c+Ω)i+(m/2)V_i(ω_c-Ω)t (1)式中 V_i 为载波幅度;ω_c 为载波角频率;Ω为调制信号角频率;m 为调制系数。如认为放大器本身无失真,式(1)表示的信号经过 LC 选频放大电路后可表示为v_0=A_iV_icos(ω_ct-(?)_0)+(m/2)A_+V_icos[(ω_c+Ω)t-(?)_+]+(m/2)A_-V_icos[(ω_c-Ω)t-(?)_-] (2)式(2)中 A_0,A_+、A_-及(?)_0、(?)_+、(?)_-分别表示放大电路对载频、上边频、下边频的放大系数及相移。若以ω_ct为基准,则载频、上边频、下边频可用三个矢量分别表 This article focuses on how to reduce the modulated wave through the LC circuit demodulation distortion and some related issues. First, the analysis of the envelope distortion Single-frequency modulated modulated wave contains the carrier frequency, the upper frequency, lower frequency three frequency components, it can be written as v_i = V_i [1 + mcosΩt] cosω_ct = V_icosω_ct + (m / 2) V_icos where ω_c is the carrier angular frequency; Ω is the angular frequency of the modulated signal; and m is the modulation factor. If the amplifier itself is not distorted, the signal represented by equation (1) can be expressed as: v_0 = A_iV_icos (ω_ct - (?) _ 0) + (m / 2) A_ + V_icos [(ω_c + Ω) A_0, A_ +, A_- and (?) in the formula (2) are as follows: _0, (?) _ +, (?) _ -, respectively, the amplifier circuit on the carrier frequency, the upper frequency, lower frequency amplification factor and phase shift. If ω_ct as a benchmark, then the carrier frequency, the frequency of the top, the bottom frequency can be used three vector table