DSP Lab-3

Laboratory 3:

Low-pass FIR Filter Design

I. Introduction

In the present project, students are required to implement and simulate a low-pass FIR filter using DSP Builder in the Simulink environment. The design has to be downloaded to the FPGA device on the Stratix EP1S25 DSP development board to perform hardware simulation and verification.

II. Theory

An FIR (Finite Impulse Response) filter, oppositely to IIR filters, has a finite response to impulse signals, which is explained because it does not have feedback. This way, FIR filters define a class of filter that has only zeros in the z-transform (the poles are in the origin z=0).

In addition, FIR filters have other characteristics that become these filters very attractive to many applications, such as linearity of phase, stability in the frequency response and constant group delay.

Equation describes an FIR filter of length K:

Where:

x and y represent the input and transformed data, respectively.

a_k is the set of constant coefficients of the filter.

(K-1) is the order of the FIR filter.

An FIR filter can also be characterized by its number of taps (K), which is the order incremented by one. The transfer function A(z) of the FIR filter is expressed as follows:

Given equation, an FIR filter is also called an all-zero filter because the frequency response is only determined by the zeros in the z-transform.

In general, FIR filters are preferred because of its linear phase characteristic and stability. However, IIR filters can be used in applications that require sharp cut-off or narrow band filters and where linear phase is not a requirement. That is because FIR filters require much higher order implementations than IIR filters for a similar performance.

III. Background about DSP Builder and the Altera EP1S25 DSP development board

Capabilities of DSP Builder and Simulink were introduced with an example design in the Tutorial: “A/D and D/A Conversion on Altera Stratix EP1S25 Development Board using Simulink and DSP Builder” [1], which contain a design targeting the 12-bit 125MHz A/D and 14-bit 165 MHz D/A converters onboard. For further information about the Stratix EP1S25 DSP development board, the student is referred to [3] and [4].

Similarly to the previous lab design, the present project will include multirate capabilities by using the PLL blocks in the Altera FPGA. The student is referred to Laboratory 1 [2] for information about working with different sampling rates in the same circuit design.

IV. Requirements

For this laboratory, students are required to accomplish the next requirements:

• Define the floating-point coefficients for a low-pass FIR filter with the next specifications:

Direct-form FIR filter

Cut-off frequency: 0.1178 x F_N

Stop-band frequency: 0.2958 x F_N

Max. attenuation pass-band: 3dB

Min. attenuation stop-band: 97dB

Use fdatool from Matlab to design the filter under the previous specifications and determine the number of coefficients. To open this tool, type ‘fdatool’ in the Matlab command window. Set the Design Method of the FIR filter to Equiripple and the Design Factor to 20. It is important to note that we are using normalized frequency F_N with a range from 0.0 to 1.0. The maximum value (1.0) corresponds to the half of the sampling rate.

• The coefficients of the designed filter using fdatool are in floating-point format. You can plot very easily the frequency response of the filter by using one of the available options in fdatool (Analysis>Magnitude Response). Check if the filter requirements are fulfilled.

• Export the coefficients from fdatool to the Matlab Workspace (File>Export…). By default, coefficients are stored in the variable ‘Num’. Then, convert coefficients to 16-bit fixed-point with the next command in Matlab:

Num1 = round (Num*2^16-1)

• Check if the new fixed-point coefficients fulfill the filter specifications. File > Import Filter from Workspace permits to analyze the fixed-point design. First, select ‘Direct-Form FIR’ from the drop down menu in Filter Structure and then type Num1 in the ‘Numerator’ field, which contains the 16-bit coefficients. In the ‘Units’ field, ‘Normalized (0 to 1)’ has to be select from the drop down menu below Sampling Frequency. Then, click Import Filter, and now you can check the frequency response of the fixed-point FIR filter. Analyze if it adjusts to the requirements and compare it with the frequency response obtained from the floating-point design.

• Implement the direct-form FIR filter in Simulink (DSP Builder) using the 16-bit fixed-point coefficients (stored in variable ‘Num1’) and the A/D and D/A converters onboard. You can use the design given in the Tutorial [1] as a template. The A/D converter must convert a sinusoidal signal to digital, filter it and finally convert it back to analog through the D/A converter. Place a SignalTap II node at the output of the filter to acquire the signal later (see Figure 1, Tutorial [1]).

NOTE: filter symmetry property should be used for efficiency.

• Simulate your filter in Simulink with different sinusoidal signals from 100KHz to 5MHz, observing at which frequencies the amplitude of the signal drops significantly.

• Introduce two additional sampling rates to your design: 2.5MHz and 10MHz, similarly to Laboratory 1. Make two additional copies of the FIR filter working at 80MHz and make the necessary modifications to have them working at 2.5MHz and 10MHz, respectively. A PLL and Tsamp blocks are required to modify the sampling rate in these two additional circuits. At the output, use a Multiplexer and two switches from SW3 onboard to select in real-time one out of the three FIR filter outputs (default at 80MHz, 10MHz and 2.5MHz).

NOTE: the Down Sampling block would not be required since the FIR filter is not combinatorial. Also, to simplify the complexity of the circuit, it is suggested to use HDL Subsystem blocks from the Altera DSPBuilder library. Each of these blocks would contain one of the three FIR filters working at different sampling rates.

• Simulate your filter in Simulink with different sinusoidal signals from 100KHz to 5MHz, observing at which frequencies the amplitude of the signal is attenuated significantly. Observe the effects of the different sampling rates, and particularly, observe the aliasing effect when working with the filter sampled at 2.5MHz.

• Download your design to the Stratix EP1S25 DSP development board and test it by using a signal generator and oscilloscope for the different sampling rate options. Observe the effect of the different sampling rates, and again, observe the aliasing effect when working with the circuit sampled at 2.5MHz.

• Capture and analyze the data using SignalTap II Analysis. Show when the amplitude of the signals drops significantly. Also, using the data acquired through SignalTap II, show the frequency response using ‘fft’ command, choosing one input signal frequency in pass-band and another in stop-band.

NOTE: you can use similar commands to those given in the Tutorial [1], “Importing the data acquired from the board in Matlab workspace”, step2.

• What happened if the bit-precision of the coefficients is fixed at 8 bits? Modify your design by replacing 16-bit coefficients by 8-bit coefficients (convert your floating-point coefficients to 8 bits), and observe the behavior. Acquire the data through SignalTap II and show the frequency response using ‘fft’ command, choosing one input signal frequency in pass-band and another in stop-band.

V. Submission

You must submit:

· The Simulink model (.mdl) developed using DSP Builder blocks with three FIR filters working at three different sampling rates: 2.5, 10MHz and 80MHz, respectively.

· A report describing the general procedure to accomplish the project requirements, and answering questions regarding filtering and aliasing effects as detailed in the requirements. The report must contain graphs showing the filtered signals and frequency response using ‘fft’ command for different sampling rates. Choose one input signal frequency in pass-band and another in stop-band. Also, discuss and show the effects of reducing the coefficient precision from 16 to 8 bits.

VI. References

[1] Tutorial: “A/D and D/A Conversion on Altera Stratix EP1S25 Development Board using Simulink and DSP Builder”.

[2] Laboratory 1: Real-Time Implementation for Observing Quantization Effects

[3] DSP Builder User Guide, ver. 5.1.0, Altera, 2005. Local copy at: c:\altera\61\DSPBuilder\Doc\ug_dspbuilder.pdf

[4] Stratix EP1S25 DSP Development Board Data Sheet, ver. 1.6, Altera, 2004. Available online at: http://www.altera.com/literature/ds/ds_stratix_dsp-board-starter.pdf or local copy at: c:\altera\61\kits\stratix_dsp_kit-v1.3.0\Docs\ds_stratix_dsp_bd.pdf

[5] DSP Development Kit Stratix & Stratix Professional Edition (Getting Started User Guide), ver. 1.3.0 rev. 1, Altera, 2004. Available online at: http://www.altera.com/literature/ug/ug_stratix_dsp_kit.pdf or local copy at: c:\altera\61\kits\stratix_dsp_kit-v1.3.0\Docs\ug_stratix_dsp_kit.pdf

Blog Traffic - Web 2.0 traffic tactics

The blogging phenomenon perfectly integrates in the second generation of web services know as Web 2.0 since this is the most convenient platform for all Internet moves. What is there for bloggers with Web 2.0? First of all, the whole aim of the new web-technology is to facilitate collaboration and sharing between users, on the one hand, and increase the usage rate on the other hand. The next legitimate question that rises here touches on the best ways to attract traffic in the conditions of the transition to blogs that are sources of highly functional content.

First and foremost, we need to say here that with blogs web information is no longer centralized in terms of authority, not to mention that the freedom to use and re-use material is limitless. From a certain point of view blogs become a real market, in which content is the transaction environment. Hence, Web 2.0 traffic tactics mainly gravitate around the optimization of blog articles for advanced search on the search engines. Though it may be very tempting, don't aim too high from the very beginning, it is almost impossible to get large numbers of visitors form the first blogging days.

The key to getting good traffic is perseverance and service quality. Content has to be re-freshed every week if not more often; in order to make that an easier task, it is enough to change some of the content, even if you don't replace it all. With the large number of applications available with Web 2.0, you should place a Google search box directly on the site, so that any user may find it comfortable to perform any further search directly from your blog page. What's there for you? You make the user spend more time on the site and, consequently, you increase the chances of his or her returning to the blog in the future.

People are now more interested in blogs that have RSS feeds; well, you'll have to let Internet users know that as soon as you can! Initially, graphics were the best means to indicate the presence of an RSS feed; the great advantage now is that you can adjust the very colors used for this attention sign to the theme or topic specific to the blog itself. The system is created in such an easy to use way that all you have to do is insert the text and the color scheme and then a graphic pattern is generated immediately.

Iomega eGo Portable Hard Drive

Who knew file storage could be so chic? The 160 GB eGo has enough room to hold up to 640,000 digital photos, 2,900 hours of music or 240 hours of video (depending, of course, on the compression rate). A new dual-interface version works over USB or FireWire and comes with both types of cords. If you accidentally knock the eGo off your desk, the shock-absorbing case will protect the important documents and precious media stored inside.

FlyTech Dragonfly

WowWee's flying insect soars, dive-bombs, hovers and glides using authentic flapping-wing action, which makes it the first commercially available toy ornithopter. It's lightweight (about 1 oz.) yet sturdy, and sports a 16-in. wingspan. The two-channel radio remote lets you control wing speed and tail rotor speed and doubles as a charging base (a 20-min. recharge gives you about 6 min. of flying time). The kids will love it — if you can bear to let them have it for a while.

Toshiba Portégé R500-S5004

This ultra thin-and-light notebook is a dream machine for road warriors. It runs on an Intel Core 2 Duo processor and offers 2 GB of RAM, an integrated DVD burner and graphics card and built-in wireless capability (both wi-fi and Bluetooth). The 12.1-in. widescreen LED-backlit display is super slim and displays in high-definition (1280 x 820 pixels). With the S5004 model you get a solid-state hard drive, which means no fragile spinning parts, so the machine is less likely to suffer damage if dropped or bumped. Total weight: 2.4 lbs.

Samsung P2

The slim and sexy P2 sounds terrific and plays a variety of music file formats: MP3, WMA and songs from subscription services like Rhapsody and Yahoo Music. The pretty 3-in. screen has touch controls for viewing photos and watching videos, which are displayed at a DVD-quality rate of 30 frames per second. The device also works with BlueTooth headsets and speakers, and soon you will be able to receive forwarded calls from a BlueTooth cell phone. (You'll have to download what's called a firmware upgrade from the Samsung website, but don't worry, it's not as difficult as it sounds.) Comes with 4 GB of memory for $200, or 8 GB for $250.

Sony Handycam HDR-CX7

The CX7 records rich high-definition footage straight to a flash memory card (Sony's Memory Stick PRO Duo), so it feels light and compact in your palm, and the 2.7-in. LCD screen features touch controls for set up and playback. Should you get the shakes while shooting, the CX7 has the ability to stabilize the image (using optics, which is more effective than a digital correction) and smooth out the action. A built-in HDMI port lets you connect the camera to an HDTV and watch your home movies in all their high-def glory.

Palm Centro

Do you secretly covet your friend's smart phone while dismissing it as way overpriced? The new Palm Centro provides an opportunity to get all the essential smart-phone features without breaking the bank. This light and bright device supports Web surfing, emailing, instant messaging and text messaging, and sports a 1.3-megapixel camera and a touch screen that works best with a stylus. A mobile version of Google Maps comes preloaded. The qwerty keypad is seriously small, but the bubble-like tactile design of the individual keys makes them easier targets.

Netgear SPH200W Wi-Fi Skype Phone

This cordless wi-fi phone comes with Skype software already built in, so you can log in to an existing account and start making cheap Internet calls immediately. If you've never used Skype before, do not fear: It takes a few moments to create a new account and you can do it right from the phone's keypad. (The first 10 minutes are free; after that, you'll want to visit Skype.com from your computer to sign up for a service plan with a credit card.) The phone will also work at most public hotspots (including T-Mobile's) so if you have lots of friends overseas, you may not want to leave home without it.

Top 10 Gadgets

1. Apple iPhone

The iPhone changed the way we think about how mobile media devices should look, feel and perform. The design is exceptional inside and out: It's got a slick glass-and-stainless steel case and an elegant touch screen loaded with eye candy. It's an iPod and a 2-megapixel camera. Images and video clips display vertically or horizontally — they reorient themselves depending on how you hold the thing. When the phone detects a wireless network within range — your own home wi-fi set up or somebody else's — it lets you tap once to connect, and then proceed with your Web surfing, Google mapping, emailing and other activities that can otherwise be painfully slow over AT&T's cellular network — the only one, unfortunately, that carries iPhone calls.

2. Nikon Coolpix S51c

Have you ever maxed out your digital camera's memory card midway through a vacation? The 8-megapixel Nikon Coolpix S51c point-and-shoot is tricked out with built-in wireless capability, so you can email your images or beam them directly from the camera to your Flickr account or to Nikon's own online photo bank. It's also got a 3x zoom and a roomy 3-in. LCD screen — and it comes in black.

Planning For Construction Cost Escalations

By Richard

Since late 2003 construction costs nationwide have been rising faster than the rate of general inflation, especially in the arid West. Various indexes have put national construction cost increases at 4 to 10 percent over the past year. Moreover, material costs nationwide have increased more than 2 percent just this September alone. And, with the impact of the recent hurricanes now being felt, construction costs are expected to rise 5 to 10 percent nationwide in the future.

Why is the West feeling the pinch? Increasing construction costs can be attributed to two major factors: an increase in new construction starts, and a shortage of materials. Current and planned construction starts alone are currently at $1.5 billion.

The effect is that architects, general contractors, engineers and sub-contractors have an abundance of work from which to chose, and therefore can now be more selective than in past years. Accordingly, competition is less price-sensitive. Since we have emerged from the "contractor surplus" seen in the early 2000's, there is now a relative "shortage" of qualified professionals to fulfill the demand of current and future projects.

Material shortages are another reason for construction cost escalations. Local material shortages are now being compounded by the nation-wide effect that the natural disasters in southeast United States have brought on. Material shortages not only add to the direct costs of materials, but can also add additional lead time to procurement. This can potentially extend the duration of project construction and additional costs in areas such as general conditions as well.

So what should owners do to put themselves in the best position for a smooth project? The following are the three most important concerns an owner should be aware of when beginning a new construction project:

1. Pick a sharp design firm. You want to ensure that the design firm you choose can give you the design aesthetics and functionality you desire, but is also looking for cost-effective solutions behind the scenes.

2. Pick a contractor with strong preconstruction services. Preconstruction is responsible for setting costs, scheduling, and determining alternative methods solutions. A reputable Construction Manager/General Contractor (CM/GC) will identify long-lead times associated with certain materials and plan for them accordingly so that there are no interruptions in construction. Also, if there are materials that are about to rise in cost, your CM/GC can order early to lock in a lower price. Additionally, it is in the preconstruction phase where your schedule is reviewed to identify if a possible shortening or shifting will enable you to realize additional savings. As you can see, having expert Development Support is critical.

3. Involve your general contractor early in the process. Many projects are started with an under-funded budget. You need to have accurate, real-time costs and data to properly prepare a budget for a project. Too often, budgets rely on dated or inaccurate information. This is why it helps to bring in a contractor early on.

While owners, architects and contractors all work together as a team, architects naturally have more control over design, while contractors have more control over costs. The earlier you bring all parties together, the less budget problems you will have later down the line.

Construction cost escalation is an issue that is not going away soon. There is no way to completely negate the issue, but with proper planning and the right construction and design teams, budgetary issues can be identified early on, and alternative method solutions can be pursued to keep your project moving forward on time and on budget.

Rich Allison oversees the Colorado office of Adolfson & Peterson Construction. He directs all estimating, scheduling, and construction project management activities, and is responsible for the strategic planning, risk management and operational decisions of the Colorado Region. For more information, see A&P's construction management resources. Rich has been involved in all aspects of A&P's business development and construction management for more than 25 years. He can be reached at 303-363-7101.

Rich Allison oversees the Colorado office of Adolfson & Peterson Construction. He directs all estimating, scheduling, and construction project management activities, and is responsible for the strategic planning, risk management and operational decisions of the Colorado Region. For more information, see A&P's construction management resources. Rich has been involved in all aspects of A&P's business development and construction management for more than 25 years. He can be reached at 303-363-7101.
Article Source: http://EzineArticles.com/?expert=Richard_Allison

Safety Tips For Builders

By Nares Mahawar

Builders should always take the correct precautions to ensure their safety on building sites. This article includes a few guidelines which you should follow as a builder to ensure your safety on a construction site. Please note that this article provides some general guidelines only and are simply recommendations from the author. For more comprehensive safety guidelines you should consult your building company.

Ladders
Builders acquiring injuries from falling off ladders are not uncommon. As a builder don't be tempted to be macho. It is important that you anchor the top end of your ladder to something secure and avoid taking risks with old broken ladders.

Scaffolding

As a builder don't be afraid to request extra scaffolding or refuse to work on it if you think it is unsafe. Scaffolding is a relatively cheap process and a lack of it is not a risk worth taking. Also don't try to take shortcuts and rearrange the scaffolding if necessary.

Lifting

Back injuries are one of the most common types of injuries experienced by builders. Back injuries are easily avoidable by using the correct lifting techniques and by avoiding trying to lift heavy loads alone. Always ask somebody to help you if the load is too heavy as you don't have to be macho just because you are on a building site. It is better than ending up with a slipped disc.

Head Injury protection

It is a common criterion of building companies working on large sites to have all their builders wearing hard hats at all times. However on small sites it is rare to find even a single hard hat available, let alone a builder wearing one. The main reason for this is that most builders working on small sites feel that hard hats are for the 'big boys only' who work on larger developments on and hence shun them at all times. However smaller sites are no less dangerous than larger ones and therefore it is certainly worth making the effort. At very minimum they should be available on the site so that they can be utilized during works where there is a risk of obtaining a head injury.

Steel toe-cap boots

Broken or bruised toes can be easily avoided by wearing toes with steel caps. Most builder merchants offer a variety of steel cap shoes which should be an essential part of any builders working outfit.

First aid kit

All builders should have a first aid kit available on site. Most injuries received on a building site are thankfully minor and can usually be fixed with some TCP and a bandage.

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LEED - Impact on New Construction

By Jeff Schaefer

We've all seen the signs indicating a new construction project is underway. In this day and age more and more are becoming environmentally conscientious. What does that mean for those who are in the Construction field? It means they need to be on the cutting edge of green technology.

What is LEED? Leadership in Energy and Environmental Design (LEED) is basically a third-party certification program. It is a nationally accepted organization for design, operation and construction of high performance green buildings. This ensures the buildings are environmentally compatible, provide a healthy work environment and are profitable.

LEED certified buildings are commanding higher rental rates and great occupancy than the non-green buildings. This trend cannot help but impact the Investment community. The supply while gradually increasing is not keeping up with the demand for green buildings. LEED buildings are awarded points for sustainability for things like energy-efficient lighting, low-flow plumbing fixtures and collection of water to name a few.

Recycled construction materials and energy efficient appliances also impact the point rating system. In the political climate of today's world, as the earth's natural resources are being depleted at an alarming rate the construction industry is being compelled to look at alternatives to traditional construction materials and styles.

More and more legislation is being passed that impacts not only zoning but environmental impact for new construction. LEED certification and Energy Star ratings seem to be the future of construction projects. It's important to not only build beautiful buildings but buildings that are energy efficient, healthy for their occupants to exist within and that they not harm the environment.

Those of us who populate those buildings can feel good about the part we are doing to help the environment and preserve what is left of the environment after years and years of taking natural resources for granted. Green technology as it continues to catch on will generate additional jobs and challenge conventional wisdoms. Look what happened in the auto industry with the electric cars. It didn't really catch on despite the fact that many who had the opportunity to test drive them wanted to keep them. Instead they were basically scrapped because of big business. Now we have hybrids and more and more companies are looking for ways to create cars that are more environmentally friendly.

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Construction Company - Requirement For Everyone

By Omar S Mahmood

Home Construction is a cumbersome task because it needs lot of time and dedicated efforts to produce desired results. Every people does not have that much experience of building construction. Its really a tough science, its does not matter you are building a new home from scratch or renovating your existing home, You need experts help, or advice every time you think of it.

Well, there are several construction consultants or construction companies with several years of relevant expertise to assist people in building their homes, shopping malls, or offices. They are not only helpful in construction, in fact they provide one stop solution of all tasks related to building or any type of civil constructions including planning, elaboration, construction, furnishing as well as interior and exterior decoration.

There are several things which only an expert can suggest better, like materials needed in making different portions, their ratio and proportion depending on the geographical location and other factors. Another problem is with the need of civil equipments needed in construction, a normal person cannot arrange every equipment for quick, efficient and perfect work. This is what you can achieve by hiring services of a construction expert only.

Construction Companies helps you determine the time required in construction as well as the budget required. There are other requirements too which needs to be finalized before shifting to your new home of office, that includes several licensing and permissions like electricity license, phone connection, cable connection, fire alarms and emergency facilities (in case of offices). Another important issue is insurance of home as well as mortgage loans installments fixation. Construction companies helps you with everything, making you relax from all worries of construction.