7/28/2019 pcm q bank

1/3

Say True or False w.r.to. 30 chl PCM. (10 x 1 = 10 M)

1. Sampling frequency for speech transmission is 8000 Hz. [ ]2. 30 Chl PCM will have 30 speech time slots. [ ]

3. Time Slot duration is 3.9 Micro Seconds [ ]

4. Frame duration is 125 nano seconds. [ ]5. Multi Frame duration is 200 milli seconds. [ ]

6. TS 16 of Frame zero carries FAW. [ ]

7. TS 16 of F1 to F15 carries Signalling information. [ ]8. 30 chl PCM bit rate is 1544Kbps. [ ]

9. 30 chl PCM signal will be in HDB-3 code format. [ ]

10. Bit repetition rate is 488 Micro seconds. [ ]

Answer the following.Each question carries Marks ( 5 x 3 = 15M )

1. State criteria for FAW selection.

2. As per the Basic PCM System configuration write the units of a TerminalEquipment.

3. State the functions of Mux Unit.4. Write the names of the units of a 2M PCM Multiplexer of 30 Chl NEC PCM

system.

5. Write the names of the test instruments required for taking tests in a PCM System.

1. FDM

2. TDM

3. PCM

4. FAW

5. AMI

6. NRZ

7. CMI

1. Write the five processing steps that are required in formation of a PCM signal. (2 M)

2. State the requirements of a Line Code. 21/2 M

3. Practical 30 Chl PCM systems use how many bits to represent a quantized sample and

what are they. Also give details. 21/2 M

7/28/2019 pcm q bank

2/3

1. Sampling frequency for speech transmission is 8000 Hz. [ ]

2. 30 Chl PCM will have 30 speech time slots. [ ]3. Time Slot duration is 3.9 Micro Seconds [ ]

4. Frame duration is 125 nano seconds. [ ]

5. Multi Frame duration is 200 milli seconds. [ ]6. TS 16 of Frame zero carries FAW. [ ]

7. TS 0 of F1 carries Signalling information. [ ]

8. 30 chl PCM bit rate is 1544Kbps. [ ]9. 30 chl PCM signal use HDB-3 Line code. [ ]

10. Bit duration is 488 Micro seconds. [ ]

Expand the following:

8. TDM

9. PAM

10. AMI

11. NRZ

1. What are the basic principles of PCM?

2. State the requirements of a Line Code.

3. Define sampling theorem.

1. What type of multiplexing method is used in PCM ? [ ]

(a) FDM (b) TDM (c) FDMA

2. _____________ no. of Timeslots are there in a Frame. [ ](a) 64. (b) 30. (c) 32.

3. Total no. of Frames in one Multiframe are ______________ [ ]

(a) 16 (b) 32. (c) 15.4. _________ Micro Sec. Is the duration of a Timeslot. [ ]

(a) 3.9 (b) 0.488 (c) 2

5. Which line code is used in 30 Chl. PCM system. [ ]

(a) AMI (b) HDB3 (c) CMI.6. How many bits are there in one Time slot? [ ]

a) 4 b) 6 c) 8

7. ______________ time slot is used for carrying the signaling informationin 30 channel PCM. [ ]

a) 16 b) 32 c) 8

8. The value of sampling frequency in PCM is _______ [ ]a) 4 KHZ b) 8 KHZ c) 2 MHZ

II. Answer the following

7/28/2019 pcm q bank

3/3

1. What are the basic principles of PCM ? ( 3 Marks )

2. Name any THREE Line codes. ( 3 Marks )3. Expand the following : ( 2 Marks )

a) AMI :b) FAW: