frequency

问题 I'm wondering if there is a way to select part of a sample at a given frequency. The only way I can think to index the sample by frequency is using an FFT, but doing that seems to mess up the sample so that it's not actually playable anymore. I was wondering how else one might select the part of a sample at a given frequency whilst keeping the sound intelligible? Edit: The exact instructions were "synthesize an example of each vowel of pitch 150 Hz and duration 5 seconds". Edit: I completely

问题 I've been reading up about this, and the numbers don't add up. On my operating system (Windows), I can check the resolution of the system clock like this: LARGE_INTEGER largeInt; // Basically a struct/union containing a long long QueryPerformanceFrequency(&largeInt); // largeInt now holds the frequency of my system's clock, it's 3903987 // This ends up being a resolution of about 256 nanoseconds All is good, but now I want to use std::chrono to check the same details. According to

问题 The task what I'm trying to do is about showing up the frequency of every single characters from the string object, for the moment I've done some part of code, just doesn't have the easy concept in my mind for finishing this task. So far I was thinking that it might be usefull to changing the char into int type. What is worth mentioning I'd like to avoid using the part: if (letter == 'a') NumberCount++; as if it wouldnt be efficient to write that much conditions for that simple task, and I

问题 I have an input sine wave which is in time domain with a frequency of 10Hz. I am trying to code in MATLAB to develop a Frequency Response Function for a 2dof modal analysis problem. In the output, there is a dominating peak at 10Hz, which is clearly due to the input harmonic wave Question: Which is the best way to remove this known harmonic disturbance from the response(output) in matlab? Also, what should I do when the disturbing harmonic is not known? Fs=1/dt; NFFT = 2 ^ nextpow2 (L); %L is

问题 Is there a simple way to extract the main frequency/period from a signal (without resorting to the FFT)? For my requirements, this can result in either a value for the main frequency (e.g. 3Hz) or a value representing the strength of a target frequency. For example, in the following 1-D signal the frequency is about 4Hz, assuming the sampling rate is 50ms. How can this be extracted from the data programmatically? 10 2 1 2 8 10 8 2 1 1 8 10 7 1 1 2 7 10 5 1 回答1: Use Auto Correlation ! %using

问题 I am new to R , I want to create a frequency table, I have a data like this, Member_id Car interest 1 FORD_MUSTANG 4 1 BUICK_Lucerne 1 1 CHEVROLET_SILVERADO 1 2 CHEVROLET_SILVERADO 1 2 FORD_MUSTANG 2 3 FORD_MUSTANG 6 I would like to have a frequency table like this: MEmber_id FORD_MUSTANG BUICK_Lucerne CHEVROLET_SILVERADO 1 4 1 1 2 2 0 1 3 6 0 0 I have tried using table(Member_id,car), but it returns me values 1 values for each car make. Appreciate any help. 回答1: Try library(reshape2) dcast

问题 I have recently started to work on some statistical problems in R and I have a query. I normally code in python and find the "collections.Counter" function quite useful. However I did not find any such equivalent command in R which was surprising since frequencies are used a lot in statistics. for e.g. I have this table (data frame) - df -> c1 c2 reading1 2 reading2 3 reading3 1 reading4 3 reading5 2 reading6 4 reading7 1 reading8 2 reading9 4 reading10 5 and I want to get this in R- value

问题 I am playing with the gyro on iPhone 4, although I am setting the gyro update rate to 100Hz motionManager.gyroUpdateInterval = 0.01; Despite that I seem to be getting the updates only with 50Hz. Does anyone have experience with that and can either confirm that number or maybe tell me what the official update frequency is? Cheers Esden 回答1: The ST chipsets used in iPhone are capable of 1KHz for Accel and 800Hz for Gyro, in theory you may be able to get that.. 回答2: Since iOS 4.2 you can run the

问题 I am trying to make a code where I can input a random sentence, and count the frequency of the times a letter returns in this string: def getfreq(lines): """ calculate a list with letter frequencies lines - list of lines (character strings) both lower and upper case characters are counted. """ totals = 26*[0] chars = [] for line in lines: for ch in line: chars.append(totals) return totals # convert totals to frequency freqlst = [] grandtotal = sum(totals) for total in totals: freq = totals

问题 its been 6 hours since I have been writing the code but to no avail, I don't no where I am making the mistake but I am making some. Its a frequency output program and output should be like this: array[8] = {6,1,7,8,6,6,1,9} Output: 6:3 1:2 7:1 8:1 9:1 But its repeating the same numbers in my code. Any help would be much appreciable. int array[8] = {6,1,7,8,6,6,1,9}; int store[8]; int a =0; int b =0; int c=0; int d = 0; store[d] = array[b]; for (d = 0; d < 8; d++){ int count=0; c = d; b = d;