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Thus, changing the separation between the elements has a significant impact on the wavenumber response of the array.

Separate the elements even more

Finally, consider the pair of images on the right where the elements are even further apart. This array response has even more peaks and valleys than theother two.

A wavenumber filter

The sum of the outputs from an array of sensor elements represents a form of wavenumber filter (much as the correct combination of resistors, capacitors, and inductors represents a frequency filter) . If we need to pass signals having one wavenumber and to suppress signals having a different wavenumber, we may be ableto adjust the separation between the elements so as to put a peak on the desirable wavenumber and to put a null point on the undesirable wavenumbers.

A two-element array is fairly limiting

Of course, with only two elements, we don't have very many degrees of freedom to work with. We could exercise more control over our wavenumber filter if wehad more elements. We could do even better if we had the ability to give each element a different weight (including a negative weight) when the signals from all the elements are added together. Finally, we could do even better still ifwe had the ability to insert a programmable time delay (phase shift) into the output from each of the elements before adding them together.

(The use of programmable time delays falls in the category of a space series that is complex rather than being purely real. Thus, that topic isbeyond the scope of this module.)

Let's apply some weights

Now let's modify our scenario and see what we can learn in the process. We are going to increase the size of the array from two to three elements. We arealso going to assume that we can apply amplification, sign reversal, or both to the element output signals before adding those signals together. The results areshown in Figure 3 . We will compare the results in Figure 3 with the results discussed earlier in Figure 2 , so this may be a good time for you to open another copy of this module in a separate browser window if you haven't alreadydone so.

Figure 3. A three-element array with weighted sensors.
missing image

The leftmost pair of images

The leftmost pair of images in Figure 3 is similar to the leftmost pair of images in Figure 2 , except that we added a third element in Figure 3 .

All three elements in Figure 3 are weighted equally prior to summation. The separation between the left and center elements is the same as in Figure 2 . The separation between the center and right elements is the same as the separationbetween the left and center elements.

The wavenumber response

The most noticeable thing about the wavenumber response for this three-element array is that the central peak is narrower than the central peak for thetwo-element array at the left of Figure 2 . In addition, the trough between the central peak and the peaks at the ends is deeper, broader, and probably flatter (although the degree of flatness is hard to determine from this plotting format) .

Questions & Answers

find the 15th term of the geometric sequince whose first is 18 and last term of 387
Jerwin Reply
I know this work
salma
The given of f(x=x-2. then what is the value of this f(3) 5f(x+1)
virgelyn Reply
hmm well what is the answer
Abhi
how do they get the third part x = (32)5/4
kinnecy Reply
can someone help me with some logarithmic and exponential equations.
Jeffrey Reply
sure. what is your question?
ninjadapaul
20/(×-6^2)
Salomon
okay, so you have 6 raised to the power of 2. what is that part of your answer
ninjadapaul
I don't understand what the A with approx sign and the boxed x mean
ninjadapaul
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
Salomon
I'm not sure why it wrote it the other way
Salomon
I got X =-6
Salomon
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
ninjadapaul
oops. ignore that.
ninjadapaul
so you not have an equal sign anywhere in the original equation?
ninjadapaul
hmm
Abhi
is it a question of log
Abhi
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salma
Commplementary angles
Idrissa Reply
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Sherica
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Sherica
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Tamia
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Uday
hi
salma
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
Kevin Reply
a perfect square v²+2v+_
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Abdirahman Reply
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
Kim Reply
or infinite solutions?
Kim
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Al
y=10×
Embra Reply
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
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rolling four fair dice and getting an even number an all four dice
ramon Reply
Kristine 2*2*2=8
Bridget Reply
Differences Between Laspeyres and Paasche Indices
Emedobi Reply
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
Mary Reply
how do you translate this in Algebraic Expressions
linda Reply
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
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit 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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