 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
PBL385821SOS Datasheet(PDF) 7 Page - Ericsson |
|
||||||||||||||||||||||||||||||
PBL385821SOS Datasheet(HTML) 7 Page - Ericsson |
|
|
7 / 9 page  7 PBL 385 82 Battery feed R13 R14 R6 Regulation: 48V, 2 • 200 Ω ∞ ∞ 47 Ω 48V, 2 • 400 Ω ∞ ∞ 75 Ω 48V, 2 • 800 Ω ∞ 180k 100 Ω No regulation: Set for low gain All feedings ∞ <22k 47 - 100 Ω Set for high gain 18k ∞ 47 Ω Set for high gain 22k ∞ 75 - 100 Ω Figure 9. Gain regulation principle. where no balancing has been done is in the order of 6 - 12 dB. To understand that the side tone is influenced by other factors like, the impedance of the line and the signal that enters the ear acoustically directly from the mouth and from the mouth through the material in the handset. The signal that enters the microphone from the earphone acoustically will also influence the return loss factor to the telephone line. To understand that the side tone network can be trimmed to form a veritable ”distortion analyser”, so that the distortion that is present from the microphone, will be the only signal entering the earphone and this signal even being small will sound very bad. It is better to induce some of the fundamental frequency back by making the balance less perfect at that frequency. This is valid for a network that is trimmed to only one frequency. It is to strive to trim the network such that it will attenuate the fun- damental and the harmonic frequencies alike throughout the different line combinations. To understand that if one of the two signals entering the balancing system from either direction, direct from microphone or via the line, is clipped, will result in a very distorted signal entering the receiver amplifier and thus the earphone. Further , to remember that side tone is a small signal that is the difference of two large signals and that the amplitude of the distortion can be up to ten times the amplitude of the fundamental frequency. Figure 10. The side tone suppression principle. A short guidance for under- standing the side tone principle. (See fig. 10.) Assuming the line impedance to be 600 Ω. ( theorethical value ) Z1 = Line impedance Z2 = The telephone set impedance 600 Ω Z1//Z2 = 300 Ω R6 will have a certain value 39 - 100 Ω to give the telephone a specified DC- characteristic and overcurrent protection. Assuming that this DC-characteristic requires R6=60 Ω, hence it will be 1/5 of the Z1//Z2. This will in transmitting mode result that 1/5 of the ac-signal that is on the line to appear across R6. What is balancing the side tone? To understand that side tone balancing is to counteract the signal, that is transmitted via the microphone and trans- mitter to the line, returning to the earphone via the receiver. That presence of a strong side tone signal is disturbing in a way that one quite instictively lowers ones own voice level thus lowering the signal level for the other party. But again, if the balance is too good (seldom the case) the earphone will feel ”dead”. In practical terms what is expected is the same amplitude of ones own voice in the ear as when not talking in a telephone. The need to lower the side tone level Z1 Z2 PBL 385 82 Tx Rx a). b). c). Zbal Line side Telephone set side 1 2 15 18 R6 R7 R9 C5 R10 R12 R11 C4 R8 17 } dB I L High limit Low limit a. b. c. |
Similar Part No. - PBL385821SOS |
|
Similar Description - PBL385821SOS |
|
|
|
Link URL |
| Privacy Policy |
| ALLDATASHEET.COM |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
