1、sample rate

sample rate發(fā)音

英：　　美：

sample rate中文意思翻譯

常用釋義：采樣率：在數字音頻中

[數]抽樣率

sample rate雙語(yǔ)使用場(chǎng)景

1、It would run every hour, to correspond with my one hour sample rate on the HMCs.───它每小時(shí)運行一次，這與HMC上一小時(shí)的取樣速率一致。

2、Some apply sample rate conversion to the digital outputs, and this conversion may be of a poor-quality.───一些應用樣品率轉變到數傳輸出，而且這轉變可能是有一個(gè)貧窮的-質(zhì)量的。

3、For longer load tests, increasing the sample rate reduces the amount of data that you collect.───對于更長(cháng)的負載測試，增加采樣速率會(huì )減少收集的數據量。

4、You might be able to correct this error by increasing the sample rate for the load test.───您可以藉由增加負載測試的取樣率修正此錯誤。

5、The external clock frequency applied to the AD7764 determines the sample rate, filter corner frequencies, and output word rate.───AD7764的采樣速率、濾波器轉折頻率和輸出字速率由外部時(shí)鐘頻率決定。

6、Measurements of the amplitude of an analog sound. The time intervals between samples is called the sample rate.───模擬聲音振幅的度量，樣本之間的間隔時(shí)間被稱(chēng)為采樣率。

7、Only a little over 160mb of data exists for around 100 LPARs with a sample rate of one hour.───對于大約100個(gè)LPAR和一小時(shí)的取樣速率，數據只有160 MB多一點(diǎn)兒。

8、Sample rate for type of action?───動(dòng)作類(lèi)型的樣品率?。

9、Do not forget to select the correct HMC sample rate, otherwise you will not see any matching data!───不要忘了選擇正確的HMC取樣速率，否則不會(huì )看到任何匹配的數據！

sample rate相似詞語(yǔ)短語(yǔ)

1、sample survey───抽樣檢查；先行甸；樣品鑒定；檢驗樣品

2、sample show───樣品展示

3、sample───n.樣品，樣本；（化驗的）抽樣；（用于新樂(lè )曲中的）節錄樂(lè )曲；確定（模擬信號）瞬時(shí)值；v.品嘗，體驗；抽樣檢驗；節錄（某一曲子，用于新樂(lè )曲中）；n.(Sample)（美、英、愛(ài)爾蘭）桑普爾（人名）；adj.樣品的，作為例子的

4、rate───n.(Rate)人名；(法、塞)拉特；n.比率，率；速度；價(jià)格；等級；vi.責罵；被評價(jià)；vt.認為；估價(jià)；責罵

5、prototype sample───樣品；初樣；原型樣品

6、sample price───樣品價(jià)格

7、sample projects───示范工程；樣板工程；示例項目；采樣方案

8、small sample───[統計]小樣本，小試樣；小包貨樣；小包貨樣，小樣本

9、sample loop───樣品環(huán)；進(jìn)樣環(huán)路

2、FM調制解調

FM調制是是恒包絡(luò )調制，基本沒(méi)有峰均比，PA利用率高，相對于幅度調制有更好的抗干擾性能，缺點(diǎn)是帶寬利用率低。

FM調制信號表示如下，其實(shí)質(zhì)是差分頻率調制，即該sample的頻率是前一個(gè)sample的頻率加上調制信號變化量，具體表現為每個(gè)sample相位的變化。

假設| x(t) | ≤ 1，則fd是相對于中心頻點(diǎn)的最大頻偏。當x(t)恒等于1時(shí)，等效為上變頻fd。

FM調制通常會(huì )拓展頻譜，這是因為頻率調制的本質(zhì)是搬頻，占用帶寬為最大的搬頻距離加上基帶帶寬，即R+2*fd，其中R為基帶信號帶寬（符號速率），調制因子dm=fd/fmax，fmax=R/2，| x(t) | ≤ 1

FM解調使用差分解調，提取相位變化量。

根據FM調制原理，t時(shí)刻調制的相位為

2*pi*fd* x(t-1)/fs+2*pi*fd*x(t)/fs

其中dt = 1/fs，相位增量為2*pi*fd*x(t)/fs，需要滿(mǎn)足在[-pi pi]的范圍內，即x(t)*fd/fs的絕對值應小于0.5，否則會(huì )造成相位溢出失真。

在保證相位無(wú)失真的情況下調整x(t)的增益可直接調整調制信號帶寬。

FM實(shí)現需要框圖如下，解調時(shí)的fs可以不等于調制時(shí)的fs，具體通過(guò)延時(shí)N來(lái)調整，不能讓相位溢出

頻譜仿真

%% Plot Spectrum of FM Modulated Baseband Signal

% Apply FM baseband modulation to BPSK source and plot its

% spectrum.

clear;close all;

% Set the example parameters.

fs = 20e3;              % Sample rate (Hz)

ts = 1/fs;              % Sample period (s)

Rs = 1e3;              % Baseband symbol rate

dm = 1;                % FM modulation factor

fd = Rs/2*dm;          % Frequency deviation (Hz)

Nup = fs/Rs;            % Up-sampling times

%%

% Create a BPSK symbol source having a duration of 1s.

%%

Nsymb = 1*Rs;

symbBpsk = (randi([0 1],Nsymb, 1)-0.5)*2;

%%

% Upsampleing BPSK symbol to fs and shape it by Raised cosine FIR pulse-shaping filter

%%

rrcFilter = rcosdesign(0.25,20,Nup,'norm');

dataRrcIn = upsample(symbBpsk,Nup);

dataRrcTemp = conv(dataRrcIn,rrcFilter);

NtailRrc = floor(length(rrcFilter)/2);

dataRrcOut  = dataRrcTemp(NtailRrc+1:end-NtailRrc);

% Scale power, normalise the power of optimum sampling point, the scale

% of FM input signal will directly determine FM bandwidth

xOptSamp = dataRrcOut(1:Nup:end);

plot(xOptSamp,'*');

x = dataRrcOut/mean(abs(xOptSamp));

plot(x,'*');

%%

% Create an FM modulator System object and modulate the input signal.

%%

MOD1 = comm.FMModulator('SampleRate',fs,'FrequencyDeviation',fd);

y = step(MOD1,x);

%%

% Create another modulator object, |MOD2|, whose frequency deviation is

% two times larger and apply FM modulation.

%%

MOD2 = comm.FMModulator('SampleRate',fs,'FrequencyDeviation',2*fd);

z = step(MOD2,x);

%%

% Plot the spectra of the two modulated signals. The larger frequency deviation

% associated with channel 2 results in a noise level that is 10 dB higher.

%%

SA = dsp.SpectrumAnalyzer('SampleRate',fs,'ShowLegend',true);

step(SA,[x y z])

%%

調整信號大小仿真

% FM link

clear;close all;

fb = 1e3; 

dm = 1;

fd = Rs/2*dm;          % Frequency deviation (Hz)

fs = 8e3;

Nup = fs/fb;

data = (randi([0 1],1000, 1)-0.5)*2;  % BPSK

figure;plot(data,'-*');

% 成型濾波器

rrcFilter = rcosdesign(0.25,20,Nup,'norm');

dataRrcIn = upsample(data,Nup);

dataRrcTemp = conv(dataRrcIn,rrcFilter);

NtailRrc = floor(length(rrcFilter)/2);

dataRrcOut  = dataRrcTemp(NtailRrc+1:end-NtailRrc);

dataIn = dataRrcOut/mean(abs(dataRrcOut));      % Scale power

% 調制相位需要控制在[-pi pi],否則會(huì )造成相位失真，即 dataIn*fd/fs的絕對值不能超過(guò)0.5

dataIn = dataIn*fs/fd*0.5;   

maxDelta = max(abs(dataIn*fd/fs))

FMMethod = comm.FMModulator('SampleRate',fs,'FrequencyDeviation',fd);

modSymb = step(FMMethod,dataIn);

FMDeMethod = comm.FMDemodulator('SampleRate',fs,'FrequencyDeviation',fd);

demodSymb = step(FMDeMethod,modSymb);

isequal(fi(dataIn,1,13,10),fi(demodSymb,1,13,10))

return

% my function

addTemp = 0;

for i = 1:length(dataIn)

    addTemp = dataIn(i)+addTemp;

    modPhase(i,1) = 2*pi*fd*addTemp*(1/fs);

end

modSymbOut = exp(1j*modPhase);

dataDemodIn = modSymbOut;

% demod

dataDemodOut(1,1) = angle(dataDemodIn(1))/(2*pi*fd/fs);

Ndelay = 1;

for i = 1:length(dataDemodIn)-Ndelay

    deltaPhase = dataDemodIn(i+Ndelay)*conj(dataDemodIn(i));

    dataDemodOut(i+1,1) = angle(deltaPhase)/(2*pi*fd/fs);

end

isequal(fi(dataIn,1,13,10),fi(dataDemodOut,1,13,10))