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Viewing 15 posts - 91 through 105 (of 125 total)
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  • 27th September 2005 at 07:14 #33405
    H.S chaya
    Guest

    What is traffic take up?> Where can I got full details on this?.

    2nd October 2005 at 05:15 #33406
    VARUN TIWARI
    Guest

    Dear Friend/ Fellows

    Can you tell me Details about GOS?

    Please send me Erlang B Formula In detail? How can be calculated the erlanb if we have N nos. of channels?

    what is formula for SWITCH capacity?

    Thanks.

    20th October 2005 at 05:49 #33407
    sridharan
    Guest

    hi

    i know the definition of erlang.and i see the erlang table.I dont know exact meening of erlang table. what is erlang table? If anybody know please help me.

    7th November 2005 at 06:33 #33408
    ak
    Guest

    hi all,
    any idea ’bout ASR.
    i know that it is signal ratio but what is it exactly.i mean how can we express it.

    22nd November 2005 at 08:08 #33409
    nana
    Guest

    I am nana. I have a problem about switching design
    course. The problem is to design telephone central Which is
    serve 1000 subscribers with calling rate 0.02 erlang,
    interoffice connection 10%,and using PCM30. Please give me the hint to solve it,
    especially about the interoffice connection. What does
    it mean? I am sorry if there are many mistakes in my
    words. Thank you very much.

    1st December 2005 at 14:22 #33410
    Cerebrum
    Guest

    Dear, akhtar nawaz!
    If you find the previosly mentioned formula for too complicated, there is another way to compute the Erlang B formula. If you can use MS Excel the solution is Poisson function:
    =(Poisson(,,False))/(Poisson(,,True)). There is and another method but it is more complicated.

    1st December 2005 at 14:25 #33411
    Cerebrum
    Guest

    Sorry but that system have changed the original message. The full syntax is:
    =(Poisson(lines,traffic intensity,False))/(Poisson(lines,traffic intensity,True)). There is and another method but it is more complicated.

    1st December 2005 at 14:33 #33412
    Cerebrum
    Guest

    Hi, Nana!
    I think that interoffice means your subscribers will make only 10% of their calls out of the exchange(switch) you are designing. That is equal to:
    1000(subscribers)x0.02(Erl)x10%=2 Erl. Only 2Erl will be yor outgoing traffic, internall traffic will be 18Erl. The other case is just the oposite.

    12th December 2005 at 11:46 #33413
    Moawia
    Guest

    Any info about the dimensioning of MGW

    13th December 2005 at 16:44 #33414
    Moawia
    Guest

    Anyone has info about voice quality testing

    14th December 2005 at 10:49 #33415
    Boko
    Guest

    Hi,

    There are a couple of vendors which have equipment for speech quality testing. I will mention QVoice by ASCOM and SwissQual (which are former employees of ASCOM as I know). In the ITU there are several standards for testing but in the end everithing is mapped to MOS (mean oppinion score) scale (bad, poor, fair, good, excellent). We are using QVoice and they have 3 different algorithms – PACE, PACE-TA and PESQ. They all map to MOS scale with certain probability.
    If you need something more specific let me know.

    Regards

    14th December 2005 at 16:17 #33416
    Moawia
    Guest

    Thanks Boko, Can you measure MOS with these equipment and is the emulation accurate and what to do to be able to make sure it is accurate.
    Can the eqt also emulate golden ear.

    15th December 2005 at 08:39 #33417
    Boko
    Guest

    Hi Moawia,

    As I know the MOS scale is subjective and is prepared by ITU based on thousands of people listenning to samples. These vendors develop their own algorithms which map these samples to the MOS scale. They are quite aquarate. These speech samples are specially designed for different languages and contain male and female voices and etc. Then the reference sample is send from the one end (ex. MS) to the other (ex. ISDN) and then again compared with the reference. According to the algorithm they are maped from 1 (bad) to 5 (excellent). For example if I remember the highest possible value with ISDN to ISDN is is 4.2 and GSM EFR to ISDN around 3.9.
    What do you mean with golden ear?

    7th February 2006 at 10:03 #33418
    ASHISH
    Guest

    WHAT IS MEANING OF TRAFFIC IN ERLONG .

    8th February 2006 at 07:24 #33419
    Cerebrum
    Guest

    Hi,ASHISH!
    Definition of Traffic Intensity: The instantaneous traffic intensity in a pool of resources
    is the number of busy resources at a given instant of time.

    Traffic intensity
    a = λ·T
    where
    λ = number of carried connections per time unit (arrival rate, call rate)
    T = mean duration of a connection or holding time

    Example
    • In a local switch the number of calls in an hour is 1800
    • The mean holding time of a call is 3 min
    a = 1800 x 3 / 60 = 90 erlang
    Typical traffic intensities per a single source are (fraction of time they are being used)
    − private subscriber 0.01 – 0.04 erlang
    − business subscriber 0.03 – 0.06 erlang
    − mobile phone 0.03 erlang
    − PBX 0.1 – 0.6 erlang
    − coin operated phone 0.07 erlang
    A load of 90 erlang is created by a population of some 2250 – 9000 private subscribers.

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