Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Q. Advanced Mobile Phone System?
Cellular systems employed cells with a radius in the range of 5-18 km. The base station usually transmitted at a power level of 35 W or less, and the mobile users transmitted at a power level of about 3 W, so that signals did not propagate beyond immediately adjacent cells. By making the cells smaller and reducing the radiated power, frequency reuse, bandwidth efficiency, and the number of mobile users have been increased. With the advent of small and powerful integrated circuits (which consume very little power and are relatively inexpensive), the cellular radio concept has been extended to various types of personal communication services using low-power hand-held sets (radio transmitter and receivers).
With analog cellular,or AMPS (Advanced Mobile Phone System), calls are transmitted in sound waves at 800 MHz to 900 MHz. This was the first mobile phone technology available in early 1980s. Digital cellular,or D-AMPS (Digital AMPS), transmits calls in bits at the same frequency as analog cellular, with improved sound quality and security. To send numerous calls at once, D-AMPS phones use either CDMA (Code Division Multiple Access) or TDMA (Time Division Multiple Access) technology; but CDMA phones won't work in TDMA areas, and vice versa. A dual-mode unit can switch to analog transmission outside of the more limited digital network.
PCS (Personal Communications Service) phones transmit at 1800 MHz to 1900 MHz and are smaller and more energy efficient. To get around the limited coverage, a dual-band digital phone (which switches to the lower digital frequency) and a trimode phone (which works in AMPS, D-AMPS, or PCS areas) has been developed. The GSM (Global System for Messaging communications) is the most widely accepted transmission method for PCS phones.
A 9.1V zener diode has a nominal voltage fall at a test current of 28mA. The internal resistance of the zener diode is 5 ohms. Find the voltage drop across the zener diode at zener
Define The universal property of NAND and NOR Gates? The NAND and NOR gates are called universal gates, because any gate can build by using these two gates. The univers
who to write resume for job
Explain the Asynchronous Decade Counter? The binary counters earlier introduced have two to the power n states. But the counters with states less than this number are as well
Example of binary subtraction - positive number Case 1. Positive number is more than negative number ( i e, answer is positive) Example subtract 4510 ( 1011012
hi there, i have to write a program for seven segments counter with three buttons to make it counting up and down from 00 to 99 so i''m looking for someone can write it..........th
ohm''s law
How can I get an oscillator to genarate a sinusoid instead of a triangle wave
if JK flip flop has 1600hz frequency .then what is the input frequency?
Explain junction transistors (npn and pnp). Junction Transistor: This transistor consists of two p-n junctions combined in one crystal as demonstrated in figure below.
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd