Q: WDM stands for?
Solution: It stands for Wavelength division multiplexing. It has same general architecture as FDM. FDM is frequency division multiplexing.
Q: In TDM, the samples occupy adjacent time slots.
Solution: The statement is true. The TDM technique is based on sampling and they occupy adjacent slots and are transmitted in a sequence.
Q: In this type of multiplexing time slots are preassigned to sources and fixed.
Solution: TDM is time division multiplexing. Data rate of medium exceeds data rate of digital signal to be transmitted.
Q: Controlling the frequency is referred as _________
Solution: It is referred to as frequency modulation. When there is a change in frequency, it is referred to as frequency modulation.
Q: A technique that can be a solution to the problem of synchronizing data sources.
Solution: Pulse stuffing is a technique that can be a solution to the problem of synchronizing data sources. In pulse stuffing, the outgoing data rate is higher than sum of incoming rates.
Q: For voice, each channel contains a ___ word of digitized data.
Solution: In digital carrier systems, for voice each channel contains one word of digitized data. The data rate is 1.544 Mbps. Five out of six frames have 8 bit PCM samples.
Q: Many time slots are wasted in __________
Solution: In Synchronous TDM, many time slots are wasted. Other techniques can help overcome this problem.
Q: A technique that allocates time slots dynamically.
Solution: Statistical TDM assigns time slots dynamically. They are allocated based on demand. Multiplexer scans input lines and collects data until the frame is full.
Q: A system in which two channels are dedicated to transfer data.
Solution: A cable modem has two dedicated channels from cable TV provider dedicated to data transfer. One in each direction.
Q: In this technique, there is a link between subscriber and network and a local loop.
Solution: In ASDL, there is a link between the subscriber and the network. It uses currently installed twisted pair cable.
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