### Create a StudySoup account

#### Be part of our community, it's free to join!

Already have a StudySoup account? Login here

# Instrument& Circuits Lab ECE 3041

GPA 3.64

### View Full Document

## 6

## 0

## Popular in Course

## Popular in ELECTRICAL AND COMPUTER ENGINEERING

This 0 page Class Notes was uploaded by Cassidy Effertz on Monday November 2, 2015. The Class Notes belongs to ECE 3041 at Georgia Institute of Technology - Main Campus taught by Staff in Fall. Since its upload, it has received 6 views. For similar materials see /class/233901/ece-3041-georgia-institute-of-technology-main-campus in ELECTRICAL AND COMPUTER ENGINEERING at Georgia Institute of Technology - Main Campus.

## Popular in ELECTRICAL AND COMPUTER ENGINEERING

## Reviews for Instrument& Circuits Lab

### What is Karma?

#### Karma is the currency of StudySoup.

#### You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!

Date Created: 11/02/15

w WW a I gr g g j 1quot CIRCUIT DESCRIPTION vi 1 O pw10 1 1f 1 05 1 050001 1 1 1 v1 1 O pulse1 1 0 If If 05 1 x 1 0 1 39 ttnn 1m 1 tour 1 v1 probe tourier analysis of square wave quot N39 POURIER ANALYSIS TEMPERATURE 27000 DEG C FOURIER COMPONENTS OIquot TRANSIENT RESPONSE Vl Dc COMPONENT 1001001E03 HARMONIC FREQUENCY FOURIER NORMALIZED PHASE NORMALIZED NO NZ COMPONENT COMPONENT DEG PHASE DEG 1 1ooosoo 12733oo 1000EOO 9009302 oooosoo 2 2000E00 2002203 1572203 9o1as01 9ooss01 3 3000E00 4244301 3333301 39 2703301 1802E01 4 4ooosoo 2002E 03 1572303 9oasso1 9027E01 5 5ooozoo 2547301 2000201 4soss01 3604E01 6 60002oo 2002503 15723 03 9054E01 9o4ss01 7 70002oo 1819E01 14292o1 6306E01 s4osz01 3 aooonoo 2002303 15723 03 9072301 9osas01 9 9000EOO 1415201 1111501 8108E01 7207E01 I H mg Jaw 132 mm glam an 5n TOTAL HARMONIC DISTORTION 4288100E01 PERCENT by 3 mph iJamba MWth n Square Wave A10 T1 N9 ja f 1 n 1N P 7 T 7T xt 7A If 7 0 I 2 1 J27f nt T c Xt39e p dt on A1f0lttlt n T d 2 1 C1 0 otherwise 2 an 2Recn 1311 2391mcn a ya ancosn2ntfp bn39Sinn39239 39t39fP N THD 100 Z dn2 TED 42879 n2 Investigating the Feasibility of Using an Analog RLC Filter in an Automotive Radar Detector By Daniel Sinto Burdell Electronics ECE 3041 L07 March 28 2007 Executive Summary In an effort to expand product offerings Burdell Electronics is considering releasing a line of lowcost radar detectors Because our environment is saturated with various radio waves radar detectors must be able to scan through that environment and pick out the appropriate bands used by police speed guns While most expensive radar detectors use a digital spectrum analyzer to detect speci c bands this report will focus on the feasibility of replacing them with a cost effective analog spectrum analyzer consisting of an RLC circuit in a bandpass lter configuration Two important criteria will dictate whether or not such a substitution is feasible the accuracy of the spectrum analyzer and the overall cost of each unit To ascertain the effectiveness of the filter the RLC circuit was assembled with values computed to meet the design specifications in regard to quality and resonant frequency Those experimental results were then simulated with both pSPICE and Multisim and then compared to a theoretical simulation produced by Mathcad Suppliers were then contacted to price an individual unit at different purchase quantities Through the analysis of the experimental results and subsequent comparison to the original design criteria it is feasible to replace a digital spectrum analyzer with an RLC circuit equivalent Though the analog spectrum analyzer performed close to the desired level of accuracy it never exceeded the specifications The overall cost of an individual unit was marginally higher than desired but can be decreased through economies of scale bringing it inline with expectations Should management choose to develop a line of radar detectors the use of an RLC circuit as a spectral analyzer will decrease production costs without degrading the overall effectiveness of the product Introduction In an effort to grow and expand into new markets Burdell Electronics BE is considering the launch of a new product line of lowcost radar detectors Recently commissioned market studies have shown that though there is currently a glut of radar detectors available to the public most are expensive There exists a serious need for an accurate and costeffective radar detection unit Because radio waves are everywhere constantly bouncing around the air a spectrum analyzer capable of detecting the different frequency bands commonly used by police radar guns X K and Ka bands will need to be implemented The digital spectrum analyzers used in pricier detection models are highly accurate but also costly An alternative to be considered is the analog spectrum analyzer implemented by the RLC circuit in Figure 1 Though keeping the cost of the unit to a minimum is of paramount importance an inexpensive radar detector that is inaccurate will be useless In order to reduce the amount of falsepositive detections the analog spectrum analyzer will need to be accurate to within 20 of the computed theoretical values up to the third harmonic s W la vO C Figure 1 Schematic of the RLC circuit used as spectrum analyzer The following formulas and de nitions as well as the context in which they are used will prove to be useful in understanding subsequent sections Spectrum Analyzer A device used to analyze the spectral components of a radio wave For the radar detector the spectrum analyzer will lter all but the police band in question Transfer Function Relates an input voltage to an output voltage The transfer function for the RLC circuit in Figure l is ii Va Qa T0 7 i 2 Eq 1 z s 1 s 7 771 11 Qa which is a bandpass lter The lter should effectively cancel out all other waves but the one we are attempting to analyze Q is the quality factor and is de ned by Q RE and the radian 1 resonant frequency is given by a 2E The resonant frequency is then 1 fa EQ 2 27T Higher values of Q will attenuate all signals but the resonant frequency which for the purpose of the radar detector the will be equal to that of one of the police bands The Design Speci cation section will detail the two criteria mentioned above cost and accuracy and delve into the speci cations of the spectrum analyzer necessary to detect one of the police bands Cadence pSPICE and NI s Multisim were used to simulate the experimental ndings while Mathcad was used to simulate theoretical values Our data is then collected displayed and interpreted in the Design Performance anal Recommendation section The bene ts and drawbacks of the analog spectrum analyzer will then be explored as well as any accuracy issues arising from the testing of the circuit It will be shown that the cost of the analog circuit tested is considerably less than the speci ed criteria and though not as precise as a digital spectrum analyzer suits our needs to within our de ned range of accuracy Thus based on the criteria of accuracy it is feasible to use a simple RLC circuit in a radar detector because it passes the resonant frequency within an acceptable margin of error Design Specifications and Criteria Criteria 39 Performance 0 The first second and third harmonics must be accurate to within a 20 error from theoretical calculations 0 Should be able to handle square triangle and ramp waveforms 0 Have a quality factor Q of 10 and a resonant frequency of 10 kHz 39 Cost 0 The total cost of the RLC circuit components may not exceed 125 Design Using a 3 mH inductor and aiming for our design criteria of Q 10 and a resonant frequency of 10 kHz we calculated the values of the individual components for use in our spectral analyzer We then used the Fluke to measure the actual values of the components The measured values listed in Table 1 could be improved by increasing the quality of the components used Table 1 Computed and measured values for the RLC circuit I Inductor I Resistor I Capacitor I Computed 3 mH 207 koth 882 nF Measured 292 mH 197 koth 6733 nF Our experimental resonant frequency was then computed from Eq 2 and was found to be 114 kHz The circuit was constructed with the measured values and then different waveforms created by an Agilent Waveform Generator were passed through the spectrum analyzer The output voltages measured by an Agilent DMM are summarized in Table 2 It should be noted that the theoretical values of the even harmonics in a square and triangle wave are 0 but the values in Table 2 suggest that there is a minimal voltage present in the circuit at all times Table 2 Measured output voltages for different wave types The prices quoted in Table 3 were compiled from our various suppliers and indicate the price per unit when a certain quantity is ordered ie if BE decides to do a production run of 1000 units than each resistor will be priced at 036 per Design Performance and We recreated our circuit from Figure l in both Multisim and pSPICE and then performed an AC sweep to generate phase and magnitude plots of our transfer function Eq 1 the results of which can be seen in Figures 2 and 3 The resonant frequency of the circuit has also been included in the magnitude plots of both figures The values found by both different computer simulations are within 45 of the 114 kHz resonant frequency we computed by hand 11 350K1 0000 mnnHm u uL11um1 ELgtgt 1 KHZ anKuz 1mm anxuz 1mm 1 PUL11UR11 Figure 2 Magnitude and phase plots genefagte dmby pSPlCE AC 1v xSZSl 800m x1 113snik a 6mm Vi 9999994m E9 400m 2 200m 1k ink muk FrequEnEya ll lUU E 5 5 o 3 a n 124 50 s M 1 39 1k 10k 100k Frequencyalz Figure 3 Magnitude and phase plots generated by Multisim Another simulation was then carried out in Mathcad with the theoretical values of the circuit components This yielded the phase and magnitude plots in Figure 4 It can be seen that the theoretical resonant frequency is actually 99 kHz which leads to an error of l 5 15 The discrepancy between the resonant frequencies in the theoretical and experimental calculations is due to the difference between the computed theoretical and measured values of the circuit components in Table 1 Though 15 may seem like a large error it can be easily and cheaply improved by substituting higher quality components and does not affect our overall recommendation of the LC spectrum analyzer Magnitude i we a y 59 J 5 2 u l in3 l in r Phase Plot 2 3 5 in u a l in3 l in r Frequency Figure 4 Magnitude and phase plots generated by Mathcad we or r T le errors were then graphed in Figure 4 The error percentages begin to in crite the realworld application ofthe radar detector the trian e wave most closely crease dramatically a er ria 0f20 For simulates that o radar used by speed detection devices and though closest to our limit is still comfortably beneath IL Error for Different Waves Error r 4 Harmonics Figure 4 Error at each harmonic for different mve forms

### BOOM! Enjoy Your Free Notes!

We've added these Notes to your profile, click here to view them now.

### You're already Subscribed!

Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'

## Why people love StudySoup

#### "I was shooting for a perfect 4.0 GPA this semester. Having StudySoup as a study aid was critical to helping me achieve my goal...and I nailed it!"

#### "I bought an awesome study guide, which helped me get an A in my Math 34B class this quarter!"

#### "I was shooting for a perfect 4.0 GPA this semester. Having StudySoup as a study aid was critical to helping me achieve my goal...and I nailed it!"

#### "Their 'Elite Notetakers' are making over $1,200/month in sales by creating high quality content that helps their classmates in a time of need."

### Refund Policy

#### STUDYSOUP CANCELLATION POLICY

All subscriptions to StudySoup are paid in full at the time of subscribing. To change your credit card information or to cancel your subscription, go to "Edit Settings". All credit card information will be available there. If you should decide to cancel your subscription, it will continue to be valid until the next payment period, as all payments for the current period were made in advance. For special circumstances, please email support@studysoup.com

#### STUDYSOUP REFUND POLICY

StudySoup has more than 1 million course-specific study resources to help students study smarter. If you’re having trouble finding what you’re looking for, our customer support team can help you find what you need! Feel free to contact them here: support@studysoup.com

Recurring Subscriptions: If you have canceled your recurring subscription on the day of renewal and have not downloaded any documents, you may request a refund by submitting an email to support@studysoup.com

Satisfaction Guarantee: If you’re not satisfied with your subscription, you can contact us for further help. Contact must be made within 3 business days of your subscription purchase and your refund request will be subject for review.

Please Note: Refunds can never be provided more than 30 days after the initial purchase date regardless of your activity on the site.