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  • Because it uses an FFT algorithm, Dsp030 is much less flexible than Dsp028 , particularly with respect to data length and selection of the frequencies of interest.
  • Because it uses an FFT algorithm, Dsp030 is much faster than Dsp028 , particularly when used to perform spectral analysis on long data lengths.

A complete listing of Dsp030 is provided in Listing 22 .

Description of the program named dsp030

This program uses an FFT algorithm to compute and display the magnitude of the spectral content for up to five sinusoids having different frequencies andamplitudes. (See the program named Dsp028 for a program that does not use an FFT algorithm.)

The input parameters

The program gets input parameters from a file named Dsp030.txt . If that file doesn't exist in the current directory, the program uses a set ofdefault parameters.

Each parameter value must be stored as characters on a separate line in the file named Dsp030.txt . The required input parameters are shown in Figure 16 . (Contrast this with the required input parameters for Dsp028 shown in Figure 12 .)

Figure 16. Required input parameters for Dsp030.
Data length as type int (must be a power of 2) Number of spectra as type int. Max value is 5.List of sinusoid frequency values as type double. List of sinusoid amplitude values as type double.

Note that in contrast with Figure 12 , the required input parameters for Dsp030 do not include the sample number representing zero time, the lower frequency bound for computation of the spectra, and the upperfrequency bound for computation of the spectra.

(The computational frequency range cannot be specified for the FFT algorithm. It always computes the spectra from zero to one unit less thanthe sampling frequency.)

Restrictions on the data length

Note also that the data length must always be a power of two. Otherwise, the FFT algorithm will fail to run properly.

(This restriction is an important contributor to the speed achieved by the FFT algorithm.)

The sinusoidal frequency values

As with Dsp028 , the number of values in each of the lists must match the value for the number of spectra.

All frequency values are specified as a double representing a fractional part of the sampling frequency.

Figure 17 shows the parameters used to produce the spectral analysis plots shown later in Figure 18 .

(Note that the data length is a power of two as required by the FFT.)

Figure 17. Example input parameters.
256 50.1 0.20.3 0.50.005 9090 9090 90

The plotting program

The plotting program that is used to plot the output data from this program requires that the program implement GraphIntfc01 . For example, the plotting program named Graph03 can be used to plot the data produced by this program. This requires that you enter the following at thecommand line prompt after everything is compiled:

java Graph03 Dsp030

The plotting program named Graph06 can also be used to plot the data produced by this program, requiring that you enter the following at thecommand line prompt:

java Graph06 Dsp030

The transform method

A static method named transform belonging to the class named ForwardRealToComplexFFT01 is used to perform the actual spectral analysis. The method named transform implements an FFT algorithm. As mentioned above, the FFT algorithm requires that the data lengthbe a power of two. This method will be discussed very briefly later.

Questions & Answers

how environment affect demand and supply of commodity ?
Amos Reply
Wht at the criteria for market ?
what is difference between monitory policy and fiscal policy?
Malik Reply
monetary policy is a policy thrust by National Govt(CBN) to influence government spending, purchase &taxes
necessity of economics
Pamela Reply
I will say want,choice,opportunity cost,scarcity,scale of preference
what is monopoly market.How price output are determined under monopoly market
b) Monopoly market is an impecfect market where s single firm having the innovation to produce a particular commodity.Prices are determined through output since there are no other competitive.
Monopoly market:firm has market power & does not respond to market price
Explain the process of price determination under perfect competition market with suitable diagram
bisham Reply
Price determination under perfect competition via this process :firms have no market power to influence price rather firms respond to market price.
price is different from demand- demand is amount of commodity
Effah Reply
demand is amount /quantity of commodity a potential buyer is willing to buy at a given price at market
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Faith Reply
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Baby Reply
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Mbah Reply
what is money
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Difine macro economics
money is a medium of exchange between goods and services,maybe inform of currency.
Economics is study of how human beings strive to satisfy numerous wants using limited available resources.
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what are implications of computing national income?.
what is the formulae for calculating national income
it calculated by value added method
classify the production units like agriculture, banking, transport etc
money is anything that is generally acceptetable for human
Estimate the net value added(NVA) at fixed cost by each industrial structure
definition of unemployment
Adam Reply
what are the causes of unemployment?
Mbubi Reply
The main causes of unemployment are listed below. 1. Frictional unemployment 2. Cyclical unemployment 3. Structural unemployment
We can also categorize the causes on a broader sense as: 1. Political and 2. Social cause As unemployeement root causes are embaded in this two.
would opportunity cost exist if there was no scarcity?
yes just because the opportunity cost arose when there is Alternative to choose among the alternatives.
I am thinking that, if our resources were unlimited, then there wouldn't be any need to forgo some wants. Hence the inexistence if opportunity cost
politics has done what?
consider time assani
I'm Emmanuel,...I taught the main cause is the change in gov't.
...Lack of capital to set up a firm respectively
I would like to bring in Educational levels can also be the cause the cause of the problem respectively
lack of skills among the new generation is the serious issue.
Where I come from , I don't see why education or personal aspects seem to do with unimployment, technically the motivation and eigerness in all works of live is there , dispite the cultural influence and physical bearriors;the thing we lacking is Government Support and open market ethics.
sorry about that-(repation). We have a over powering ethical political system that's displacing the marketing asspects of economy and causing large scale unemployment right across the board...
can someone Explain Expansionary Monetary Policy and Contractionary Monetary Policy Using one of the instrument of Monetary Policy? Please am kinda lost here?. ta
Emmanuel Reply
using a graph show the case of substitute and compliment goods
Ade Reply
can anyone give me a simple explanation to Five Sector Macroeconomics?
Can someone please define what economics is
jason Reply
economics simply is a social science subject that study human behavior.
economics is a social science which studies human behaviour as a relationship between ends and scarce means that has alternative uses
Can someone please tell me how to calculate GDP
emmanual kapal to calculate GDP (Gross Domestic Product) has three method in calculating it (1)income approach (2) expenditure approach (3) value added method
thanks Alae
u are welcome
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what is the law of demand
Berlinda Reply
keep other thing constant, when the price increases demand decrease when the price decreases demand increases of the commodity.
all things being equal,quantity demanded decrease as price increase and increase as price decrease
there's practial joke to it ..." the higher the demand ; scarcity, increase in production and drop in quality"... quite the controversy - for example China vs Europe, United States and we are all boxed up in between somewhere...
Other thing remain constant the low price of commodity the high quantity of commodity and vice versa is true
Explain Effective demand
Anita Reply
What is effective demand
like Modi is in demand...best example of effective demand
Don't get you
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level of demand that represents a real intention to purchase by people with the means to pay
Difference between extinct and extici spicies
Amanpreet Reply
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Source:  OpenStax, Digital signal processing - dsp. OpenStax CNX. Jan 06, 2016 Download for free at https://legacy.cnx.org/content/col11642/1.38
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