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 Wysłany: Nie 8:44, 12 Gru 2010 Temat postu: stivali ugg FM distortion FM source measurement _4 |
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Measurement of FM Distortion FM source
] Wu set of Hydraulic and Electric College. Construction materials. Water Conservancy and Electric Power Press,[link widoczny dla zalogowanych], 1983j】. Measurement of FM Distortion FM source. To the plug 7 '(Liaoning Jinxi 386J0 naval forces metering station, J25000) on the journal paper No. J】 993 of \First,[link widoczny dla zalogowanych], the FM and FM demodulation distortion distortion between the source frequency in the FM process, the use of nonlinear devices for frequency modulation (currently most used FM varactor directly.) Therefore,[link widoczny dla zalogowanych], the nonlinear distortion. This distortion is caused in the frequency, so called frequency modulation distortion. FM demodulation distortion is the so-called FM signal demodulated by demodulator, the output audio signal analyzer with the distortion measured on the distortion of the audio signal that they are two different solid concept for this distortion. FM distortion of a variety of testing methods: J. When the frequency modulation distortion device itself is much larger than the demodulation distortion, use a modulation apparatus of the FM signal into the FM source # inch He can be a ★ ● -, a measurement technology】 994. № 7 line demodulation. Then use the instrument to FM demodulation distortion distortion measurements. To measure the source of the FM distortion. 2 When the source of the FM frequency modulation distortion is less than or equal to the modulation and demodulation distortion device itself, the first method can not be used, can be measured to achieve the measurement of linear frequency modulation FM distortion FM source purposes. Second, the results of measurement and data processing block diagram of the theoretical basis for this diagram and test and measurement methods see [2] 1VPERFORMANCETESTS4 - 8FMDistortionPerformanceTest and 4-13TheRela-tionshipBetweenFMLinearityandFMDistortion part, which is in [】] the corresponding part of the same. Note: The carrier modulation partial disabilities (such as 400MHz ± 400kHz), the number of meter readings should be recorded as r + and a, the frequency modulation distortion. J + A as one random 4 - *. · +: × 1oo, is a supervisor ×】 0o a Xl00%, z a (×] 0o + ~ loo ~) / s A x] oo ~ c, examples of the instruments: 8840A digital voltmeter; VP of a 7220C; low frequency signal source; HP8902A modulation apparatus according to the aforementioned method and connection to the HP] i715A FM source for testing using a different carrier offset, t-test results the following table,[link widoczny dla zalogowanych], Table 1 carrier frequency Feng, (MII2) that the quiet chatter Yu (kII2) what vessels off with disabilities (kII2 distortion d () {001O {000.008100l04000.03012.5101000.067】】 000.069 Table 2I set L (t ~ ltz) the amount of Bong, {kilt) ± (kltz constricted true ¨) 400l04000 .008100 l0 000.007I12.5】】】 2500】 0 0 l】 『2.500l5 by Table 1 and Table 2 shows that the selected carrier off the table】 inappropriate. HPI1715A-type block diagram of FM source as below: ... the source using the same 400MHz frequency voltage controlled oscillator, and in the carrier frequency 400MHz, the frequency offset range of 0 ~ 400kHz, by the formula: output frequency, a +(),( style '】 I in () for the modulated signal, K is a proportional constant), at the center frequency of 400.4MHz,, range: a, +], that is, between the 399.6MHz ~ 400.4MHz. If the carrier frequency of 100MHz at the deviation from the 400kHz, 400MHz equivalent at off 400kHzX4, which】. 6MHz, beyond the source of the given index. Off at the 12.5MI-lz] 00kHz, equivalent to 400MHz at off 100kHzX32, ie 3.2MHz, also beyond the scope of the source given, so in Table 1 the selected frequency deviation is inappropriate,[link widoczny dla zalogowanych], Table 2 election was reasonable. In addition, this method measures the demodulator output of the relative changes in the exchange (not DC), modulation meter to avoid the distortion introduced themselves, and by measuring the distortion and HPI1715A given index _ (≤ 0.025) compared match. References [1] TAO + FM FM demodulation source measurement technology distortion measurement + + l993.1. _2] HPI1715AAM/FMTESTSOURSEOPERATION & SERVICEMANUAL. E33 Zhang Su Wen, \
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