TTMER2: Call Paths Testing - "In-circuit" measurements on ISDN and VOIP network elements
Control questions
You must give an answer to 5 questions at the beginning of the laboratory exercise. One wrong answer will make the mark given to the measuring with one grade worse. Two or more wrong answers will result a supplementary measuring!
- How to model an analogue channel?
- Give the definitions of the network-characteristic functions used also in the measuring practice!
- What is the criterion of the distortionless signal transmission in the frequency domain?
- Enumerate the distortions of a not exactly linear channel!
- Give the characteristics of a narrowband noise measuring signal!
- What kind of measures are executed on a PCM telecommunication channel for the determination of quality of the channel?
- What does MTTS mean?
- How large is the absolute enhancement of the +3,5 dBr of input, and -3,5 dBr of output connection level channel?
- Input connection level of a -7 dB nominal enhancement channel +3,3 dBr, and its output connection level is -3,4 dBr. How large is the difference of the enhancement from the nominal value? Is this kind of difference allowed?
- What influence is upon the relative connection levels, if we raise the attenuation of channel units at the sides of the transmitter and the receiver?
- What is the auxiliary signal? What is the purpose of the auxiliary signal at the measurement of the basic noise?
- What are dBu, dBm, dBm0, dBm0p, dBr? Where can the dBm0, and the dBr be derived?
- Give the principle of the enhancement measure. With what kind of variable parameters and measuring signals can the measurement be executed?
- How can the measure of drive of a channel be determined from a linearity measurement?
- Give the principle of the quantizing distortion measurement!
- What is the psophometer?
- A measure must be executed with a signal levelled at -10 dBm0. Measuring signal must be fed into at a point levelled on +3,5 dBr/600 ohms. Signal level can be set in dBu. How large is the value of level set on the generator?
- We give a sinusoid signal at the level of -25 dBm0 to the input of a channel with connection level of +3,5 dBr/600 ohms. Level of the second harmonic of the signal at the output point of -3,5 dBr/600 ohms is -68,5 dBm. How large is the second harmonic attenuation of distortion?
- We give a signal with a level of -10 dBm0 to the input of the channel with connection level of +3,5 dBr/600 ohms. How large is the level of the received signal in dBm0 at the output of the channel which has a connection level of -3,5 dBr/600 ohms?
- How can we examine the correctness of the operation of channel filters?
- How Hz-s of sinusoid signal can be resulted by a sinusoid signal of 8500 Hz-s given to the input of the PCM speech channel from the signal lapstreak?
- What does hybrid mean? Give the principle of operation of the hybrid!
- How can you measure the hybrid closing attenuation of an analogue interface of an exchange?
- What are MSS and MSSN? How many MSS are located in the MSSN of the laboratory?
- What is Media Gateway?
- Draw the hardware block scheme of a Media Gateway implemented in MSS!
- Review the main functions of the Media Gateway!
- Review some procedures used for the handling of the voice channels in VoIP!