# Honglei Chen

### MathWorks

Last seen: 3 jours il y a Actif depuis 2011

Followers: 1   Following: 0

I am a developer on Phased Array System Toolbox at MathWorks

DISCLAIMER: Any advice or opinions posted here are my own, and in no way reflect that of MathWorks.

Professional Interests: Signal Processing, Array Processing, Radar, and Communication

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Extra safe primes
Did you know that the number 5 is the first safe prime? A safe prime is a prime number that can be expressed as 2p+1, where p is...

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Basic electricity in a dry situation
&#9889 &#9889 &#9889 &#9889 &#9889 &#9889 &#9889 &#9889 &#9889 &#9889 &#9889 &#9889 &#9889 &#9889 &#9889 &#9889 &#9889 &#9889 &#...

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Pentagonal Numbers
Your function will receive a lower and upper bound. It should return all pentagonal numbers within that inclusive range in ascen...

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Pernicious Anniversary Problem
Since Cody is 5 years old, it's pernicious. A <http://rosettacode.org/wiki/Pernicious_numbers Pernicious number> is an integer w...

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Tick. Tock. Tick. Tock. Tick. Tock. Tick. Tock. Tick. Tock.
Submit your answer to this problem a multiple of 5 seconds after the hour. Your answer is irrelevant; the only thing that matte...

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Energy of a photon
*&#9883 &#9762 &#9883 &#9762 &#9883 &#9762 &#9883* Given the frequency F of a photon in giga hertz. Find energy E of this...

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How to subtract?
*&plusmn &plusmn &plusmn &plusmn &plusmn &plusmn &plusmn &plusmn &plusmn &plusmn &plusmn* * Imagine you need to subtract one...

plus de 6 ans il y a

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Fahrenheit to Celsius using multiple statements
Given a Fahrenheit value F, convert to a Celsius value C. While the equation is C = 5/9 * (F - 32), as an exercise use two state...

presque 9 ans il y a

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Data Regularization
Provided is an m-by-n integer data matrix A whose elements are drawn arbitrarily from a set *S* = [1,2,3,...,S] for any large in...

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Which values occur exactly three times?
Return a list of all values (sorted smallest to largest) that appear exactly three times in the input vector x. So if x = [1 2...

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Compute the step response of a DC motor
Compute the step response of a DC motor shown below <<http://blogs.mathworks.com/images/seth/cody/dc-motor.png>> The param...

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Model a simple pendulum
Model a simple pendulum of length 200cm with bob of mass 100g and plot the position in degrees. The pendulum starts at 30 degree...

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Produce a Fibonacci sequence
Construct a diagram that generates the Fibonacci sequence: 1, 1, 2, 3, 5, 8, 13, 21, 34.....up to 377 The Fibonacci sequ...

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Make a low pass filter
Make a first order low pass filter that will filter out the high frequency oscillations for the given input signal. The cut-off ...

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Model a falling body
An object is falling freely from a height of 22 meters under the force of gravity. <<http://blogs.mathworks.com/images/seth/c...

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Model a mass spring system
Model an ideal mass-spring system shown below where the spring is initially stretched. <<http://blogs.mathworks.com/images/se...

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Counting pulses in a signal
Count the number of pulses that are the result of summing each pulse generator block. Pulse Generator blocks produce a recurr...

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Add damping to a mass spring system
Model an ideal mass-spring-damper system shown below where the spring is initially stretched. <<http://blogs.mathworks.com/im...

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Make a full wave rectifier
Produce a full wave rectifier waveform for the given sine wave source. For a sine wave input, the output of the full wave rec...

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Make a half wave rectifier
Produce a signal that outputs the given sine wave source when it is greater than zero and outputs zero when it is less than zero...

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Produce a sine wave
Produce a sine wave with amplitude 3: <<http://blogs.mathworks.com/images/seth/cody/sine-eqn.png>>

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Produce the following signal: <<http://blogs.mathworks.com/images/seth/cody/add-offset-eqn.png>> You should see a downward...

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Add a block to a model
Produce the following signal: <<http://blogs.mathworks.com/images/seth/cody/add-block-eqn.png>> In this case, the slope of...

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Produce a cosine wave
Produce the following signal: <<http://blogs.mathworks.com/images/seth/cody/cosine-eqn.png>>

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Connect blocks in a model
Connect the blocks in the model to produce the following signal: <<http://blogs.mathworks.com/images/seth/cody/connect-blocks...

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Nearest Numbers
Given a row vector of numbers, find the indices of the two nearest numbers. Examples: [index1 index2] = nearestNumbers([2 5 3...

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Simple equation: Annual salary
Given an hourly wage, compute an annual salary by multiplying the wage times 40 and times 50, because salary = wage x 40 hours/w...

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Who Has the Most Change?
You have a matrix for which each row is a person and the columns represent the number of quarters, nickels, dimes, and pennies t...

environ 9 ans il y a

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Circle area using pi
Given a circle's radius, compute the circle's area. Use the built-in mathematical constant pi.

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Find the alphabetic word product
If the input string s is a word like 'hello', then the output word product p is a number based on the correspondence a=1, b=2, ....

presque 12 ans il y a