Line Coding
July 15, 2022 | Author: Anonymous | Category: N/A
Short Description
Download Line Coding...
Description
Chapter 1 Line Code Encoder
1-1: Curriculum Objectives
1.To understand the theory and applications of line code encoder. 2.To understand the encode theory and circuit structure of NRZ. 3.To understand the encode theory and circuit structure of RZ. 4.To understand the encode theory and circuit structure of AMI. 5.To understand the encode theory and circuit structure of Manchester.
1-2: Curriculum Theory Line coding is a part of source coding. Before PCM signal send to modul at or , we us e cer t ai n s i gnal mode i n cer t ai n appl i cat i on. The considerations of selecting the digital signal modes to carry the binary data are: 1. types of mo dulat ion, 2. t ypes o f dem odul ation , 3. the l imita tion of ba band ndwi widt dth, h, and 4 ty type pess of receiver. Line coding can be divided into two types, which are return-to-zero (RZ) and nonreturn-to-zero (NRZ). RZ line coding denotes for a single bit time (normally is half of a single single bit bit time), time), the the waveform waveform will will return return to 0 V betwee betw een n da data ta pu pulse lse s.
The data stream is shown in figure 1 -1(c). NRZ line coding denotes for a single bit time, the waveform will not return to 0 V. The data stream is shown in figure 1-1(a). As a result of the charact eristics of signal, line coding also can be divided into two types, which are unipolar signal and bipolar signal. Unipolar signal denotes that the signal amplitude varies between a positive voltage level which are +V and 0 V. The only different between bipolar signal and unipola r signal is the signal amplitude varies betwe be tween en a positi pos itive ve and a nega n egativ tivee volt v oltage age level lev el which whi ch are +V and an d -V. Figure Fig ure 11-1 1 shows sho ws different types of line code signals and we will discuss the encodi encoding ng sign signals als in next next secti section. on.
1. Unipolar Nonreturn-to-zero Signal Encode The data stream of unipolar nonreturn-to-zero (UNI-NRZ) is shown in fugure 1-1(a). From figure 1-1(a), 1-1(a), when the data bit is “1”, the width and the gap between bits of UNI-NRZ UNI-NRZ are equal to each others; when the data bit is “0”, then the pulse is represented as 0V. The circuit circuit diagram of UNI-NRZ encoder is shown in figure 1-2. As a result of the data signal and the the NRZ encoder signal are similar, therefore, we only need to add a buffer in front of the circuit.
Figure 1-2 Circuit diagram of unipolar nonreturn-to-zero encoder. 2.
Bipolar Nonreturn-to-zero Signal Encode
The data stream of bipolar nonreturn-to-zero (BIP-NRZ) is shown in figure 1-1(b). When the data bit of BIP-NRZ is "1" or "0", the signal amplitude will be a positive or a negative voltage level. As for bit time, no matter the data bit is "1" or "0", "0", the voltage level remain remain same. Figure Figure 1-3 is the circuit diagram of BIP-NRZ encoder. By comparing the data data streams streams of UNI-NRZ a BIP-NRZ, the only differen ce is the signal amplitude is a negativ e voltage l evel when th e data bit is "0", t herefore, we m ay utilize a co compa mpara rato torr to encode the data bit in the circuit.
3.
Unipolar Return-to-zero Signal Encode The data stream of unipolar return-to-zero (UNI-RZ) is shown in figure 1-1(c). When
the data bit is "1", the s ignal amplit ude at 1/ 2 bit time i s positi positive ve volt voltage age level level and the rest rest of the bit time is represented as 0 V. When the data bit is "0", there is no pulse wave that means the signal amplitude is 0 V. The bit time of RZ is half of the bit time of NRZ , therefore, the required bandwidth bandwi dth of o f RZ is one time more more than NRZ. However, However, RZ has two phase phase
variations in a b it time, which is easy for receiver syn chronization. From figure figure 1-1, compare the data signal, clock signal and data after encoding, we know that in order orde r to obtain the encoding data of RZ, we need to "AND" the data signal and clock signal. The circuit diagram of unipolar unipola r return re turn-to-zero -to-zero encoder encoder is show shown n in figu figure re 1-4. 1-4.
Figure 1-3 Circuit diagram of bipolar nonreturn-to-zero encoder. encoder.
Figure 1-4 Circuit diagram of unipolar return-to-zero encoder.
4. Bipolar Return-to-zero Signal Encode The data stream of bipolar return-to-zero (B1P-RZ) is shown in figure 1-1(d). When the data bit is "1", th e signal amplitude at 1/2 bit time is positive positive voltage voltage level and and the other 1/2 bit time is negative voltage level. When the data bit bit is "0", the signal signal amplitude of the bit time is represented as negative voltage level. Figure 1-5 is the circuit diagram of BIP-RZ. By comparing the data streams of RZ and BIP-RZ in figure 1-1, we only need a converter to convert the encoding signal from unipolar to bipolar, therefore, we utilize a comparator to design the converter, which can convert the RZ signal to BIP-RZ signal.
Figure Fig ure 1-5 Circuit Circuit diagram diagram of bipolar return-to-zer return-to-zero o encoder. encoder. 5. Alternate Mark Inversion Signal Encode Alternate mark inversion inversion (AMI) (AMI) signal is similar to RZ signal except th thee alt a lt er nate na te " 1" inver ted. T he dat a stream of AMI sig nal is s hown i n figure figure 1-1(f). 1-1(f). When the data data bit is "1", the first first signal signal amplitu amplitude de at 1/2 bit bit time is pos itive volt age le vel an d the other 1/2 b bit it ti me is 0 V; th en th e se seco cond nd signa sig nall ampl am plit itud udee at 1/ 1/2 2 bi bitt t ime is nega ne gati tive ve volta vo lta ge level and the other 1/2 bit time 0 V, therefore, the only different between AMI and RZ i s the alternate "1" are inverted. When the data bit is "0", the signal amplitude is 0V. Thi s t ype of enc ode is com mon use d b y t ele pho ne in indu dust stry ry wh whic ich h is pu puls lsee co codi ding ng modulation (PCM).
Figure 1-6 is the circuit diagram diagram of AMI signal encode. In order to obt ain th e AMI encode signal, the data and clock signals need to pass through the buffer stage, which is comprised by a pair of transistors and NOT gates. After that we need to "AND" the output of data signal and clock signal, then pass through a divider circuit by utilizin g c lock as swit ch exchange. exchange. The final signal signal is the the AMI signal. signal. The minimum minimum ba nd widt wi dth h of AMI AM I i s le less ss than th an UNIUN I- RZ and an d BI BIP P -R -RZ. Z. An addi ad diti tion onal al adva ad vant ntag agee of AM AMII i s the transmission errors can be dete cted b y detecting the violation s of the al alte tern rnat atee-on onee rule.
Figure 1-6 Circuit diagram of AMI signal encoder.
6. Manches t er Si gnal Encode
Manchester signal is also known as split-phase signal. The data stream of Manchester signal is shown in figure 1-1(e). When the data bit is "1", the signal amplitude at first 1/2 bit time is positive voltage level and the other 1/2 bit time is negative voltage level. When the data bit is "0", the signal amplitude at first 1/2 bit time is negative voltage level and the other 1/2 bit time is positive voltage level. This type of encode signal has the advantage of memory, therefore, the required bandwidth is larger than the other encode signals. So, it is suitable applied to network such as Ethernet. From figure 1-1, compare the data signal, clock signal and data after encoding, we know that in order to obtain the encoding data of Manchester, we need to "XNOR" the data signal and clock signal. Figure 1-7 is the circuit diagram of Manchester signal encoder.
Figure 1-7 Circuit diagram of Manchester signal encoder.
1-3 : Experiment Items Experiment 1: Unipolar and bipolar NRZ signal encode Experiment 1-1: Unipolar NRZ signal encode
1. To implement a unipolar NRZ encode circuit as shown in figure 1-2 or refer to figure DCT1-1 on GOTT DCT-6000-01 module. 2. Setting the frequenc y of function gene rator to 1 kHz T TL signal and connec connectt tthis his signal to the Data I/P. Then observe on the output waveform by using oscilloscope and record the measured results in table 1-1. 3. According to the input signals in table 1-1, repeat step 2 and record the measu measure red d results in table 1-1. Experiment 1-2: Bipolar NRZ signal encode
1. To implem ent a b ipolar NR Z signal encode circuit as shown in figure 11-3 3 or or rref efer er to figure DCT1-1 on GOTT DCT-6000-01 module. 2. Setting the frequency of function generator to 1 kHz TTL signal and connect this signal to the Data I/P. Then observe on the waveforms of TP1 and BIP-NRZ O/P b y using oscilloscope and record the measured results in table 1-2. 3. According to the input signals in table 1 -2, repeat step 2 and record the measu measure red d results in table 1-2.
Experiment 2 : Unipolar and Bipolar RZ signal encode Experiment 2-1 : Unipolar RZ signal encode
1. To implement a unipolar RZ signal encode circuit as shown in figure 1-4 or refer to figure DCT 1-2 on GOTT DCT-6000-01 module. 2. Setting the frequency of function generator to 2 kHz TTL signal and connect this signal to the CLK I/P of figure DCT 1-2 and CLK at the left bottom. After that connect the Data O/P at the left bottom to the Data I/P in figure DCT 1-2. Then observe o bserve on the waveforms wavefo rms of o f CLK I/P, Data I/P and UNI-RZ UNI-RZ O/P O/P by using using oscillosco oscilloscope, pe, and record the measured results in table 1-3.
3. According to the input signals in table 1-3, repeat step 2 and record the measured results in table 1-3. 4. Setting the frequency of function function generator to 2 kHz TTL signal and c onne ct this signal to the CLK I/P in figure DCT 1-2. Then setting another frequenc y of fu nctio n genera tor to 1 kH z T TL signal and connec connectt tthis his si signa gnall to the Data Data I/P I/P in in fig figure ure DCT1-2. DCT1-2. Then Then obse observe rve on the wa ve fo rm of CL K I/P , Da ta I/P and UNI-RZ O/P by using oscilloscope, Hid record the measured results in table 14.
5. According to the input signals in table 1-4, repeat step 4 and record the measured results in table 1-4.
Experiment 2-2 : Bipolar RZ signal encode
1. To implement a bipolar RZ signal encode circuit as shown in figure 5 or refer to figure DCT1-2 on GOTT DCT-6000-01 module.
2. Setting the frequency of function generator to 2 kHz TTL signal and connect this signal to the CLK I/P in figure DCT1-2 and CLK at the left bottom. After that connect the Data O/P at the left bottom to the Data I/P in figure DCT1-2. Then observe on the waveforms of CLK I/P, Data I/P, TP1 and BIP-RZ O/P by using oscilloscope, and record the measured results in table 1-5.
3. According to the input signals in table 1-5, repeat step 2 and record the measured results in table 1-5.
4. Setting frequency of function generator to 2 kHz TTL signal and connect this signal to the CLK I/P in figure DCT1-2. Then setting another anoth er frequency of function generator to 1 kHz TTL signal and connect this signal to the Data I/P in figure DCT1-2. Then observe on waveforms of CLK I/P, Data I/P, TP1 and BIP-RZ O/P by using oscilloscope, and record the measured results in table 1-6.
5. According to the input signals in table 1-6, repeat step 4 and record the measured results in table 1-6.
Experiment 3 : AMI signal encode 1. To implement an AMI signal encode circuit as shown in figure 1-6 or refer to figure
DCT 1-3 on GOTT DCT-6000-01 module.
2. Setting the frequency of function generator to 2 kHz TTL signal and connect this
signal to the CLK I/P in figure DCT 1-3 and CLK at the left bottom. After that connect the Data O/P at the left bottom to the Data I/P in figure DCT1-3. Then observe on the waveforms of CLK I/P, Data I/P, TP1, TP2, TP3, TP4, TP5 and AMI O/P by using oscilloscope, and record the measured results in table 1-7.
3. According to the input signals in table 1-7, 1 -7, repeat step 2 and record the measured results in
table 1-7.
4. Setting the frequency of function generator to 2 kHz TTL signal and connect
this signal to the CLK I/P in figure DCT1-3. Then setting another frequency of function generator to 1 kHz TTL signal and connect this signal to the Data I/P in figure DCT1-3. Then observe on the waveforms of CLK I/P, Data I/P, TP1, TP2 , TP3 , TP4 , TP5 and AMI O/P by using oscilloscope, and record the measured results in table 18. 1 -8, repeat step 4 and record the measured results in 5. According to the input signals in table 1-8, table 1-8.
Experiment 4: Manchester signal encode 1. To implement a Manchester signal encode circuit as shown in figure 1-7 or refer to figure DCT1-4 on GOTT DCT-6000-01 module. 2. Setting the frequency of function generator to 2 kHz TTL signal and connect connect this signal to the CLK I/P in figure DCT 1-4 and CLK at the left bottom. After that connect the Data O/P at the left bottom to the Data Data I/P in figure DCT1-4. Then observe on the waveforms waveforms of CLK I/P, I/P, Data I/P I/P and Manche ster O/P by usin g oscillo scope, and record the measured results in table 1-9. 3. According to the input signals in table 1-9, repeat step 2 and record the meas measur ured ed results in table 1-9. 4. Setting the frequency of function generator to 2 kHz TTL signal and connect this signal to the the CLK I/P in figure DCT1-4. Then setti setting, ng, anot her freq uency of func tion gene rato r to 1 kHz TTL s igna l and connect connect this signal signal to the Data I/P in figure fig ure D DCT CT 1-4. 1-4. Then Then observ observee on the wave forms of CLK I/P, Da ta I/P and Ma nc he st er O/ P b y u si ng oscill oscillosc oscope, ope, and reco record rd the the meas measure ured d resul results ts in in table table 1-10. 1-10. 5. According to the input signals in table 1-10, repeat step 4 and record the measured results in table 1-10.
1-4 : Measured Results
Table 1-1: Measured results of UNI-NRZ signal encode.
Output Signal Waveforms Input Signal Frequencies (Data I/P)
1 kHz
2kHz
5kHz
8kHz
UNI-NRZ O/P
Table 1-2 Measured results of BIP-NRZ BIP-NRZ signal encode.
Output Signal Waveforms Input Signal Frequencies (Data I/P)
2 kHz
3.5 kHz
5kHz
7.5 kHz
TP1
BIP-NRZ O/P
Table 1-3 Measured results of UNI-RZ signal encode.
Output Signal Waveforms Input Signal Frequencies (Data I/P)
2 kHz
3.5 kHz
5kHz
7.5 kHz
CLK I/P
Data I/P
UNI-RZ O/P
Table 1-4 Measured results of UNI-RZ signal encode. Input Signal Frequencies
CLK I/P
Data I/P
2 kHz
1 kHz
3.5 kHz
1.5 kHz
5kHz
2.5 kHz
7.5 kHz
4 kHz
Output Signal Waveforms
CLK I/P
Data I/P
UNI-RZ O/P
Table 1-5 Measured results of BIP-NRZ BIP-NRZ signal encode. Input Signal Frequencies (Clock I/P)
Output Signal Waveforms CLK I/P
Data I/P
TP1
BIP-RZ O/P
CLK I/P
Data I/P
TP1
BIP-RZ O/P
2 kHz
5kHz
Table 1-6 Measured results of BIP-NRZ BIP-NRZ signal encode. Input Signal Frequencies CLK I/P
2 kHz
5kHz
Output Signal Waveforms
DATA I/P
1 kHz
CLK I/P
Data I/P
TP1
BIP-RZ O/P
CLK I/P
Data I/P
TP1
BIP-RZ O/P
2.5 kHz
Table 1-7 Measured results of AMI signal encode. Input Signal
Output Signal Waveforms
Frequencies (CLK I/P) CLK I/P
Data I/P
TP1
TP2
TP3
TP4
TP5
AMI O/P
100 Hz
Table 1-7 Measured results of AMI signal encode. (Continue) Input Signal
Output Signal Waveforms
Frequencies (CLK I/P)
500 Hz
CLK I/P
Data I/P
TP1
TP2
TP3
TP4
TP5
AMI O/P
Table 1-8 Measured results of AMI signal encode. Input Signal Frequencies CLK I/P
100 Hz
Output Signal Waveforms
Data I/P
50 Hz
CLK I/P
Data I/P
TP1
TP2
TP3
TP4
TP5
AMI O/P
Table 1-8 Measured results of AMI signal encode. (continue) Input Signal Frequencies CLK I/P
500 Hz
Output Signal Waveforms
Data I/P
250 Hz
CLK I/P
Data I/P
TP1
TP2
TP3
TP4
TP5
AMI O/P
Table 1-9 Measured results of Manchester signal encode.
Output Signal Waveforms
Input Signal Frequencies (CLK I/P)
2k
3k
5k
8k
CLK I/P
Data I/P
Manchester O/P
Table 1-10 Measured results of Manchester signal encode. Input Signal Frequencies
CLK I/P
Data I/P
2 kHz
1 kHz
3.5 kHz
1.5 kHz
5kHz
2.5 kHz
8 kHz
4 kHz
Output Signal Waveforms
CLK I/P
Data I/P
Manchester O/P
1-5 : Problem Discussion
1.
Explain what are the common types of line coding ?
2.
Explain how the unipolar and bipolar nonreturn-to-zero signals encode ?
3.
Explain how the unipolar and bipolar return-to-zero signals encode ?
4.
Explain how the AMI signal encodes ?
5.
Explain how the Manchester signal encodes ?
6.
Explain why do we need line coding ?
Chapter 2 Line Code Decoder
2-1: Curriculum Objectives 1.
To understand the theory and applications of line code decoder.
2.
To understand the decode theory and circuit structure of NRZ.
3.
To understand the decode theory and circuit structure of RZ.
4.
To understand the decode theory theo ry and circuit structure of AMI.
5.
To understand the decode theory and circuit structure of Manchester.
2-2: Curriculum Theory For digital transmission transmission system, the advantages advantages of the applications of line code are as follow : (1) Self-synchronization
Line code signal has the advantage of sufficient timing information, which can make the bit synch roniz er c atch es t he timin g or pu lse sign al accur accurat atel ely y to ac achi hiev evee se self lf-synchronization.
(2) Low Bit Error Rate
Digital signal can be recovered by comparator, which can reduce the interference of noise and bit error rate. Besides we can also add a suitable device such as match filter at the receiver to reduce the affection of intersymbol interference (ISI).
(3) Error Detection Capability
The communi cation system has the ability of error detection or corre correcti ction on by adding the cha nnel encodin g and decodin g to the line c ode si sign gnal al..
(4) Transparency
By setting the line code signal and data protocol, we can receive any da data ta sequence accurately.
Figure 2-1 shows different types of line c ode signal waveforms and we wi will ll discuss the decoding signals in next section. 1. Unipolar Nonreturn-to-zero Signal Decode
Figure 2-2 shows the circuit diagram of unipolar nonreturn-to-zero (UNI-NRZ) decoder. From figure 2-1, we notice that the waveforms between UNI-NRZ signal and da ta signal are simila r to ea ch oth er. Therefor Therefore, e, we only need to add add a b buf uf fe r in fr on t of th e de co d er ci rc u it , which can recover the original input data signal.
Figure 2-1 Different types of line code signal waveforms.
Figure 2-2 Circuit diagram of unipolar nonreturn-to-zero decoder. 2. Bipolar Nonreturn-to-zero Signal Decode Figure 2-3 shows the circuit diagram of bipolar nonreturn-to-zero no nreturn-to-zero (BIP-NRZ) decoder. The signal amplitude of BIP-NRZ is either positive voltage level or negative voltage level. Therefore, for decoder, we can utilize a diode to change the negative voltage level to zero voltage level, and then we can recover the original input data signal.
Figure 2-3 Circuit diagram of bipolar nonreturn-to-zero decoder. decoder.
3. Unipolar Return-to-zero Signal Decode Figure 2-4 shows the circuit diagram of unipolar return-to-zero (UNI-NRZ) decoder. The output of the UNI-RZ decoder is a NOR-RS flip-flop, which is comprised by R ɜ, R 4 and two NOR gates. TP2 is the “S” terminal and TP3 is the “R” terminal. The clock signal will be inverted by a NOT gate which is comprised by the NOR gate. A After fter that by using XOR to operate the inverted clock signal and UNI-RZ signal; and then
p pas as si n g th ro ug h a di ff er e n ti at or wh ic h is co mp ri se d b y C 2 and R 2 , t he output will be transformed transf ormed to pulse pulse wave which which is used for "R" "R" terminal terminal of RS flip-flo p as shown in TP 1 and TP3 of figure 2-5. UNI-RZ signal will pass through a capacitor to the "S" terminal of RS flip -flop, as sho wn in TP2 of figure 2-5. Finally by sending both UNI-RZ and clock clo ck signals sign als into the RS flip-flop, flip-flop, we can can recover the origina originall input data signal. signal.
Figure 2-4 Circuit diagram of unipolar return-to-zero decoder.
Figure 2-5 Output waveforms of unipolar return-to-zero decoder.
4. Bipolar Return-to-zero Signal Decode As we know the difference between UNI-RZ and BIP-RZ is the UNI-RZ has only positive volt age level , neverthel ess BIP-RZ has both positive positive and nega negative tive voltage level. Therefore, we utilize a diode to chan ge the negative voltage level to zero voltagee level voltag level as shown in figure figure 2-3, then we ca n ob tain a UNI-R Z signa l. Aft er th at, the UNI-RZ signal will pass through a UNI-RZ decoder circuit as shown in figure 2-4, then we can recover the original input data signal. 5. Alternate Mark Inversion Signal Decode From figure 2-1, compare the RZ with AMI encode waveforms, we know that if the negative voltage level of AMI transforms to positive voltage level, the encode waveform is exactly similar to RZ encode waveform. Therefore, the AMI decoder can be divided divided into two two parts, which which are the circuit of AMI transfo rm to RZ an d the ci rcuit o f RZ decoder. The circuit circuit diagrams of UNI-RZ UNI-RZ decoder and AMI transfor transform m to RZ are shown in figures 2-4 and 2-6, respectively. From figure 2-6, when the AMI signal locates at positive voltage level, the signal will pass through D 2 to OUT; on the other hand, when the AMI signal locates at negative voltage level, the signal sign al will pass through D 1 , which is connected to the comparator, and then pass through D 3 to OUT. Therefore,, we can abtain the RZ signal from AMI signal. Therefore
Figure 2-6 Circuit diagram of alternate mark inversion decoder. 6.
Manchester Signal Decode From figure 2-1, com pare the data signal, clock signal and en code signal, signal, we
need to invert the clock signal, and then use an XOR to operate the inverted clock signal signal and Manch Manchest ester er signa signal. l. Final Finally ly,, we can obtai obtain n the origi nal dat a enc ode sig nal . Fig ure 2-7 sh ows th e circ uit d iagra m of Manchester Manchester decoder. decoder. From figure figure 2-7, the objective of the first XOR to operate the clock signal and +5 V signal is to invert the clock signal, then the second XOR to operate the inverted clock signal and Manchester signal is to recover the original input data signal.
Figure 2-7 Circuit diagram of Manchester decoder.
2-3: Experiment Items Experiment 1: Unipolar and bipolar NRZ signal decode Experiment 1-1: Unipolar NRZ signal decode 1.
Using the UNI-NRZ encode circuit as shown in figure 19-2 of chapter 19 or refer to
figure DCT 1-1 on GOTT DCT-6000-01 module to produce the UNI-NRZ signal. 2.
To implement a UNI-NRZ decode circuit as shown in figure 2-2 or refer to figure
DCT2-1 on GOTT DCT-6000-01 module. 3.
Setting the frequency of function generator to 1 kHz TTL signal and connect this signal to the Data I/P of figure DCT1-1. Then connect the UNI-NRZ 0/P of figure DCT11 to the UNI-NRZ I/P of figure DCT2-1. Next observe on the output waveform by using oscilloscope oscillo scope and record the measured measured result resultss in table 2-1. 2-1.
4.
According to the input signals in table 2-1, repeat step 3 and record the measured measured
results in table 2-1.
Experiment 1-2: Bipolar NRZ signal decode 1.
Using the BIP-NRZ encode circuit as shown in figure 19-3 of chapter 19 or refer to figure
DCT1-1 on GOTT DCT-6000-01 DCT-60 00-01 module modu le to produce produ ce the BIP-NRZ BIP-NRZ signal signal.. 2.
To implement a BIP-NRZ decode circuit as shown in figure 2-3 or refer to figure DCT2-1
on GOTT DCT-6000-01 module. 3.
Setting the frequency of function generator to 1 kHz TTL signal and connect connect
this signal to the Data I/P of figure DCT1-1. Then connect the B1P-NRZ O/P of figure DCT1-1 to the BIP-NRZ BIP-NRZ I/P I/P of figure figure DCT2-1. Next observe on the output wave form by using oscilloscope and record the measured results in table 2-2. 4.
According to the input signals in table 2-2, repeat step 3 and record the measu measure red d
results in table 2-2.
Experiment 2: Unipolar and bipolar RZ signal decode Experiment 2-1: Unipolar RZ signal decode 1.
Using the UNI-RZ encode circuit as shown in figure 19-4 of chapter 19 or refer to
figure DCT1-2 on GOTT DCT-6000-01 module to produce the UNI-RZ signal. 2.
To implement a UNI-RZ decode circuit as shown in figure 2 -4 or refer to fig figur uree
DCT2-2 on GOTT DCT-6000-01 module. 3.
Setting the frequency of function generator to 1 kHz TTL signal, then connect
this signal to the CLK I/P of figure DCT 1-2, as well as CLK at the left bottom and CLK I/P of figure DCT2-2. After that connect the Data O/P at the left bottom to the Data I/P in figure DCT1-2. Then connect the UNI-RZ O/P of figure DCT 1-2 to the UNI-RZ I/P of figure DCT2-2. Next observe on the waveforms of UNI-RZ I/P, TP1, TP2, TP3, TP4 and Data O/P by using oscilloscope. Finally record the measured results in table 2-3.
4.
According to the input signals in table 2-3, repeat step 3 and record the meas measur ured ed
results in table 2-3.
5.
Setting the frequency of function generator to 2 kHz TT L signal and connect this
signal to the CLK I/P in figure DCT1-2. Then setting another frequency of function generator to 1 kHz TTL signal and connect this signal to the Data I/P in figure D CT1-2. Next Ne xt conn co nnec ectt the th e UNIUN I- RZ O/P O/ P of DCT1 DC T1 -2 to UNIUN I-RZ RZ I/P of DCT2 DC T2-2 -2.. Then Th en obse ob serv rvee th thee waveforms of UNI-RZ O/P, TP1, TP2, TP3, TP4 and Data I/P by using oscilloscope, then record the measured results in table 2-4.
6.
According to the input signals in table 2-4, repeat step 5 and record the measured results in
table 2-4.
Experiment 2-2: Bipolar RZ signal decode 1.
Using the BIP-RZ encode circuit as shown in figure 19 -5 of chapter 19
or refer to figure DCT1-2 on GOTT DCT-6000-01 module to produce the BIP-RZ signal. 2.
To implement a transformation circuit of BIP-RZ to UNI-RZ as shown in
figure 2-3 and a BIP-RZ decode circuit as shown in figure 2-4 or refer to figure DCT2-2 on GOTT DCT-6000-01 module. 3.
Setting the frequency of function generator to 2 kHz TTL signal, then
connect this signal to the CLK I/P of figure DCT 1-2, as well as CLK at the left bottom and CLK CLK I/P of figure DCT2-2. After After that connect the Data O/P at the left bottom to the Data I/P in figure DCT 1-2. Then connect the BIP-RZ O/P of figure DCT1-2 to the BIP-RZ I/P of figure DCT2-2. Next observe on the waveforms of BIP-RZ I/P, TP1, TP2, TP3, TP4 and Data O/P by using oscil loscope. losc ope. Finally Fina lly reco rd the meas ured re resu sult ltss in ta tabl blee 22-5. 5. 4.
According to the input signals in table 2-5, repeat step 3 and record the
measured results in table 2-5. 5.
Setting the frequency of function generator to 2 kHz TTL signal and
connect this signal to the CLK I/P in figure DCT1-2. Then setting another frequency of function generator to 1 kHz TTL signal and connect this signal to the Data I/P in figure DCT1-2. Next connect the BIP-RZ O/P of DCT 1-2 to BIP-RZ I/P of DCT2-2. Then observe on the waveforms of BIP-RZ I/P, TP1, TP2, TP3, TP4 and Data O/P by using oscilloscope, then record the measured results in table 2-6.
6.
According to the input signals in table 2-6, repeat step 5 and record the
measured results in table 2-6. Experiment 3: AMI signal decode 1.
Using the AMI encode circuit as shown in figure 19-6 of chapter 19 or refer to
figure DCT1-3 on GOTT DCT-6000-01 module to produce the AMI signal. 2.
To implement a transformation circuit circui t of AMI to RZ as shown sho wn in figure 2-6 or refer to
figure DCT2-3 on GOTT DCT-6000-01 module. 3.
Setting the frequency of function generator to 2 kHz TTL signal, then connect this
signal to the CLK I/P of figure DCT 1-3, as well as CLK at the left bottom and CLK I/P of figure DCT2-3. After that connect the Data O/P at the left bottom to the Data I/P in figure DCT1-3. Then connect the AMI O/P of figure DCT1-3 to the AMI I/P of figure DCT2-3. Next observe on the waveforms of AMI I/P, TP1, TP2, TP3, TP4, TP5, TP6 and Data O/P by using oscilloscope. Finally record the measured results in table 2-7. 4.
According to the input signals in table 2-7, repeat step 3 and record the measured
results in table 2-7. 5.
Setting the frequency frequency of function generator to 2 kHz TTL sig signal nal and conne ct th is
signal to the CLK I/P in figure DCT1-3. Then setting another frequency of function generator to 1 kHz TTL signal and connect this signal to the Data I/P in figure DCT1-3. Nex t connec con nectt the AM I O/ P o f DC T 1 -3 t o AM I I/ P o f DC T2 - 3 . Th e n ob s e rv e o n th e waveforms of AMI I/P, TP1, TP2, TP3, TP4, TP5, TP6 and Data O/P by using oscilloscope, oscillos cope, then record the measured results in table 2 -8. 6.
According to the input signals in table 2-8, repeat step 5 and record the measured
results in table 2-8.
Experiment 4: Manchester signal decode 1.
Using the Manchester encode circuit as shown in figure 19-7 of chapter 19 or
refer to figure DCT 1-4 on GOTT DCT-6000-01 module to produce the Manchester signal. 2.
To implement a Man chester decode circuit as shown in figure 2 -7 or ref refer er
to figure DCT2-4 on GOTT DCT-6000-01 module. 3.
Setting the frequency of function generator to 2 kHz TTL signal, then
connect this signal to the CLK I/P of figure DCT1-4, as well as CLK at the left botto bo ttom m and an d CLK CL K I/P of figur fig uree DCT2DCT 2-4. 4. After Aft er that tha t conn co nnec ectt th thee Da ta O/ O/P P at th thee le ft bo tt om to the th e Data Da ta I/P in figu fi gu re DCT1 DC T1 -4. -4 . Th en conne con nect ct the Manch Man cheste esterr O/P of figure DCT 1-4 to the Manchester I/P of figure DCT2-4. Next observe on the waveforms of Manchester I/P, TP1 and Data O/P by using oscilloscope. Finally record the measured results in table 2-9. 4.
According to the input signals in table 2-9, repeat step 3 and record the
measured results in table 2-9. 5.
Setting the frequency of function generator to 2 kHz TTL signal and
connect this signal to the CLK I/P in figure DCT1-4. Then setting another frequency of function generator to 1 kHz TTL signal and connect this signal to the Data I/P in figure DCT1-4. Next connect the Manchester O/P of DCT1-4 to Manchester I/P of DCT2-4. Then observe the waveforms of Manchester I/P, TP1 and Data O/P by using oscilloscope, then record the measured results in table 2-10. 6.
According to the input signals in table 2-10, repeat step 5 and record the
measured results in table 2-10.
2-4 Measured Results Table 2-1 Measured results of UNI-NRZ signal decode. Input Signal
Output Signal Waveforms
Frequencies (Data I/P)
1 kHz
2 kHz
4 kHz
UNI-NRZ I/P
Data O/P
Table 2-2 Measured results of BIP-NRZ signal decode. Input Signal
Output Signal Waveforms
Frequencies (Data I/P)
1 kHz
2 kHz
4 kHz
BIP-NRZ I/P
Data O/P
Table 2-3 Measured results results of UNI-RZ signal decode. decode. ( f CLK = = 1 kHz ) TEST POINT
OUTPUT WAVEFORMS
TEST POINT
UNI-RZ TP1 I/P
TP2
TP3
TP4
Data O/P
OUTPUT WAVEFORMS
Table 2-3 Measured results results of UNI-RZ signal decode. decode. (Continue) CLK
( f
= 2 kHz ) TEST
TEST
OUTPUT WAVEFORMS
OUTPUT WAVEFORMS POINT
POINT
UNI-RZ TP1 I/P
TP2
TP3
TP4
Data O/P
Table 2-4 Measured results results of UNI-RZ signal decode. decode. ( f CLK = = 1 kHz
f CLK = = 2 kHz ) TEST
TEST
OUTPUT WAVEFORMS
OUTPUT WAVEFORMS POINT
POINT
UNI-RZ TP1 I/P
TP2
TP3
TP4
Data O/P
Table 2-4 Measured results results of UNI-RZ signal decode. decode. ( f CLK = = 1 kHz
f CLK = = 3 kHz ) TEST
TEST
OUTPUT WAVEFORMS
OUTPUT WAVEFORMS POINT
POINT
UNI-RZ TP1 I/P
TP2
TP3
TP4
Data O/P
Table 2-5 Measured results of BIP-RZ signal decode. ( f CLK = = 2 kHz) TEST
TEST
OUTPUT WAVEFORMS
OUTPUT WAVEFORMS POINT
POINT
BIP-RZ TP1 I/P
TP2
TP3
TP4
Data O/P
Table 2-5 Measured results of BIP-RZ signal decode. ( f CLK = = 3 kHz) TEST
TEST
OUTPUT WAVEFORMS
OUTPUT WAVEFORMS POINT
POINT
BIP-RZ TP1 I/P
TP2
TP3
TP4
Data O/P
Table 2-6 Measured results of BIP-RZ signal decode. ( f CLK = = 1 kHz f CLK = = 2 kHz) TEST
TEST
OUTPUT WAVEFORMS
OUTPUT WAVEFORMS POINT
POINT
BIP-RZ TP1 I/P
TP2
TP3
TP4
Data O/P
Table 2-6 Measured results of BIP-RZ signal decode. ( f CLK = = 1.5 kHz f CLK = = 3 kHz) TEST
TEST
OUTPUT WAVEFORMS
OUTPUT WAVEFORMS POINT
POINT
BIP-RZ TP1 I/P
TP2
TP3
TP4
Data O/P
Table 2-7 Measured results of AMI signal decode. ( f CLK = = 100 Hz ) TEST
TEST
OUTPUT WAVEFORMS
OUTPUT WAVEFORMS POINT
AMI I/P
TP2
POINT
TP1
TP3
TP4
Data O/P
Table 2-7 Measured results of AMI signal decode. ( f CLK = = 500 Hz ) TEST
TEST OUTPUT WAVEFORMS
POINT
AMI I/P
TP2
OUTPUT WAVEFORMS POINT
TP1
TP3
TP4
Data O/P
Table 2-8 Measured results of AMI signal decode. ( f CLK = = 1 kHz
f CLK = = 2 kHz ) TEST
TEST
OUTPUT WAVEFORMS
OUTPUT WAVEFORMS POINT
AMI I/P
TP2
POINT
TP1
TP3
TP4
Data O/P
Table 2-8 Measured results of AMI signal decode. ( f CLK = 1.5 kHz
f CLK = 3 kHz ) TEST
TEST
OUTPUT WAVEFORMS
OUTPUT WAVEFORMS POINT
AMI I/P
POINT
TP1
TP2
TP3
TP4
Data O/P
Table 2-9 Measured results of Manchester signal decode. Input Signal
Output Signal Waveforms
Frequencies (CLK I/P)
2 kHz
Manchester I/P
TP1
Data O/P
5 kHz
7 kHz
Table 2-10 Measured results of Manchester signal d decode. ecode. Input Signal Frequencies
Output Signal Waveforms
Data
Manchester
I/P
I/P
TP1
CLK I/P
2 kHz
1 kHz
Data O/P
1.5 3 kHz kHz
8 kHz
4 kHz
2-5: Problem Discussion 1. Explain what are the advantages of line code? 2. Explain how the unipolar and bipolar nonreturn-to-zero signals decode? 3. Explain how the unipolar and bipolar return-to-zero signals decode?
4. Explain how the AMI signal decodes? 5. Explain how the Manchester signal decodes? 6. Give an actual example of the application of line code.
View more...
Comments
