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Could continue adding elements tothe array

Although I won't demonstrate it, I can tell you that if I were to continue adding elements in this manner to increase the length of the array, the centralpeak and the peaks at the folding wavenumbers would continue getting narrower, and the trough between the peaks would continue getting deeper and probablyflatter.

A more selective wavenumber filter

In other words, when viewed as a wavenumber filter, a long array with more elements is a moreselective wavenumber filter than a short array with fewer elements. By properly designing an array to act as a wavenumber filter, it is possible to cause that filter to be veryselective.

When we use a properly designed array to produce a directional antenna, it is possible to produce a highly directional antenna (and avoid wasting our valuable radio frequency energy by sending it to cows and cotton plants).

A weighted three-element array

Continuing with our three-element array scenario, let's take a look at the center pair of images in Figure 3 and compare them with the leftmost images in Figure 3 .

For this case, the array still contains three elements with the same spacing as before. However, the electrical output from the center element is amplifiedto make it twice as strong as the outputs from the other two elements before the three electrical signals are added together.

Note that the array elements are no longer shown as being white against a black background in the very top of the top-center image. Instead, thecenter element is white but the other two elements are greenish indicating different weights.

It is a little hard to tell what this does to the central peak in the wavenumber response, but it definitely changes the shape of the response in thetrough between the peaks. Whether or not this would be a beneficial change would depend on the problem being addressed.

A three-element array with negative weighting

Finally, take a look at the rightmost pair of images in Figure 3 . Once again, the array contains three elements and the center element is weighted twice asheavily as the other two. In addition, the sign of the electrical signals from the two outer elements is inverted before the three are added together.

Note that the black color represents the smallest algebraic value. Negative values are smaller than positive values. Therefore, the background(which represents a weigh of zero) has changed from black to something between green and blue. The two elements withthe negative weights are shown as black and the element with the positive weight is shown as white.

The wavenumber response

This has a major impact on the wavenumber response of the three-element array.

There is no longer a peak at a wavenumber value of zero. Rather, there is now a null point at zero wavenumber as indicated by the black and blue colors at thecenter of the plot. There is now a peak on each side of zero (as indicated by the white and red colors) , half way between zero and the folding wavenumber.

Questions & Answers

how do I set up the problem?
Harshika Reply
what is a solution set?
Harshika
find the subring of gaussian integers?
Rofiqul
hello, I am happy to help!
Shirley Reply
please can go further on polynomials quadratic
Abdullahi
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Mark
I need quadratic equation link to Alpa Beta
Abdullahi Reply
find the value of 2x=32
Felix Reply
divide by 2 on each side of the equal sign to solve for x
corri
X=16
Michael
Want to review on complex number 1.What are complex number 2.How to solve complex number problems.
Beyan
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Mark
use the y -intercept and slope to sketch the graph of the equation y=6x
Only Reply
how do we prove the quadratic formular
Seidu Reply
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Darius
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Shirley Reply
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Opoku
what is math number
Tric Reply
4
Trista
x-2y+3z=-3 2x-y+z=7 -x+3y-z=6
Sidiki Reply
can you teacch how to solve that🙏
Mark
Solve for the first variable in one of the equations, then substitute the result into the other equation. Point For: (6111,4111,−411)(6111,4111,-411) Equation Form: x=6111,y=4111,z=−411x=6111,y=4111,z=-411
Brenna
(61/11,41/11,−4/11)
Brenna
x=61/11 y=41/11 z=−4/11 x=61/11 y=41/11 z=-4/11
Brenna
Need help solving this problem (2/7)^-2
Simone Reply
x+2y-z=7
Sidiki
what is the coefficient of -4×
Mehri Reply
-1
Shedrak
the operation * is x * y =x + y/ 1+(x × y) show if the operation is commutative if x × y is not equal to -1
Alfred Reply
An investment account was opened with an initial deposit of $9,600 and earns 7.4% interest, compounded continuously. How much will the account be worth after 15 years?
Kala Reply
lim x to infinity e^1-e^-1/log(1+x)
given eccentricity and a point find the equiation
Moses Reply
A soccer field is a rectangle 130 meters wide and 110 meters long. The coach asks players to run from one corner to the other corner diagonally across. What is that distance, to the nearest tenths place.
Kimberly Reply
Jeannette has $5 and $10 bills in her wallet. The number of fives is three more than six times the number of tens. Let t represent the number of tens. Write an expression for the number of fives.
August Reply
What is the expressiin for seven less than four times the number of nickels
Leonardo Reply
How do i figure this problem out.
how do you translate this in Algebraic Expressions
linda Reply
why surface tension is zero at critical temperature
Shanjida
I think if critical temperature denote high temperature then a liquid stats boils that time the water stats to evaporate so some moles of h2o to up and due to high temp the bonding break they have low density so it can be a reason
s.
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris 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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