Advantages and disadvantages of FDM

The most important application of FDM (frequency division multiplexing)  is broadcasting, telephone communications. In this article, you will find a lot of pros and cons of FDM to better understand this topic. 


Advantages of FDM:
  • It does not need synchronization between its transmitter  as well as receiver
  • FDM is simpler and easy demodulation
  • Less expensive
  • FDM system does not need synchronization but TDM needs synchronization. It is an advantage of  FDM over TDM
  • FDM provides more latency than TDM
  • Using FDM system  multimedia data can be transferred with very high efficiency and low noise and distortion 
  • FDM system has high reliability
  • It is used for analogue signals
  • In this system due to slow narrowband fading, only one channel gets affected
  • A large number of the signal can be transmitted simultaneously

Disadvantages of  FDM:
  • It is suffering the problem of cross talk
  • FDM is only used only when a few low-speed channels are desired
  • Intermodulation distortion takes place
  • The  circuitry for FDM is complex than TDM
  • FDM requires more hardware than TDM
  • FDM system extremely expensive
  • FDM provides less throughput
  • FDM has not dynamic coordination
  • The full bandwidth of the channel cannot be used on the FDM system
  • The communication must have very large bandwidth
  •  A large number of modulator and filter required 
  • FDM channel can get affected wideband fading 
  • FDM system needs a carrier wave or carrier signal but TDM does not need carrier signal

2G technology features

2G technology uses digital signals and this digital signal uses for voice transmission. This signal provides services to deliver text and picture message at low speed (in around kbps range). Here this post gives information about 2G technology features to better understand this topic.

2G technology is a second-generation wireless telephone technology, It is based on the technology known as the global system for mobile communication or in short we can say GSM. 2G technologies enabled the various mobile phone network to provide services such as text message, picture message, and also  MMS called multimedia messages. All text message is digitally encrypted. This digital encryption allows for the transfer of data in such a way that only the intended receiver can receive and read it.

Basic key features of 2G technology:
  • Utilized digital signal processing rather than the analog signal used in 1G.
  • Digital signaling processing allowed the network to support data transfer as well as the voice traffic previously supported by analog signaling
  • 2G became very popular because the user was capable of connecting their mobile devices to the internet and business work.
  • It supports phone calls.
  • It provides better quality and capacity.
  • It supports MMS
  • 2G technology has steadily improved with increased bandwidth as well as packet routing, and the introduction of multimedia.
  • 2G provided speeds of 135 Kbps to customers at its peak.
  • It can uses send/ receive an email message.
  • 2G is a digital version of 1G technology.
  • 2G technology became very popular because users were capable of connecting their mobile device to the internet and business networks.
  • 2G technology is utilized in digital signaling processing rather than the analog signaling used in 1G.
  • 2G technology support voice as well as data.
  • TDMA, as well as CDMA technology, must be used for multiple access
  • 2G technology must be used digital signal processing so it allowed a network to support data transfer as well as the voice traffic previously supported by analog signaling.
  • 2G became very popular because the user was capable of connecting their mobile devices to the internet and business network.
  • It takes time 6 to 9 minute  to download a 3 minute MP3 songs

Difference between zigbee and wifi

Zigbee technology is designed to carry a small amount of data over a short distance while it consuming very little power, while in WiFi is a mesh networking standard, meaning each node in the network is connected to each other. This post gives information about the difference between ZigBee and wifi to better understand this topic.

The main key difference between Zigbee and WiFi is given below:

  • Zigbee has IEEE 802.15.4 and ZigBee Alliance, While Wifi has IEEE 802.11 series.
  • Zigbee as WPAN network, WiFi has WLAN network type.
  • Zigbee has 868/915 band and 2.4 GHz frequency, WiFi has 2.4 GHz and 5 GHz.
  • Zigbee has about 1 MHz channel bandwidth, while WiFi has 0.3 to 0.6 or 2 MHz channel bandwidth.
  • Zigbee has star and mesh type topology used, WiFi has BSS, ESS configuration used.
  • Zigbee has BPSK, OQpsk modulation type while WiFi has OFDM, CCK, QPSK,64QAM, 16QAM,256QAM modulation techniques used.
  • Data rate up to 250 Kbps low data rate, while WiFi up to 54 Mbps using 802.11a/g/OFDM technique, even more, is achievable using 802.11n, 11ac,11ad standard based products.
  • In Zigbee typical distance coverage around 10 to 30 meters, while WiFi 30 to 100 meters distance covered.
  • Zigbee managed by alliance and IEEE, WiFi Alliance and IEEE.
  • Number of RF channel in ZigBee 1(868MHz), 10(915MHz), 16(2.4GHz)  while WiFi 14(2.4GHz)
  • Zigbee chip cost $2 less per device than WiFi device at high volume.
  • Zigbee chip or module has a power consumption of 0.39 watts over WiFi chip of 0.87 watts.
  • Transmitted power of ZigBee is -25dbm to 0 dBm while WiFi 15 to 20 dBm.
  • Data protection using CRC is 16 bit while WiFI 32 bit CRC.
  • Zigbee is used for home automation, while WiFi is used for cellular connection within home.
  • Popular Zigbee chip is Freescale, Texas, Marvell, ATMEL, Microchip while WiFi chip Texax instruments, redpine, microchip, Broadcom, etc.

Advantages and disadvantages of microcontroller

This post gives information about the advantages and disadvantages to better understand this topic.

Advantages of the microcontroller:
  • The low time required for performing the operation
  • It is easy to use, troubleshooting and system maintenance is simple
  • At the same time, many tasks can be performed so the human effect can be saved
  • The processor chip is very small and flexibility occurs
  • Due to their higher integration, cost and size of the system is reduced
  • The microcontroller is easy to interface additional RAM, ROM, and I/O port
  • Once microcontroller is programmed then they cannot be reprogrammed
  • Without any digital parts, it can act as microcomputer
  • It is easy to use, troubleshooting and system maintaining is simple
Disadvantages of the microcontroller:
  • It is generally used in micro equipment
  • It has a more complex structure as compared to microprocessor
  • The microcontroller cannot interface a higher power device directly
  • It only performed a limited number of executions simultaneously

Advantages and disadvantages of microprocessor

A microprocessor is a basic computer-based processor that incorporates the function of a central processing unit on a single integrated circuit, or at most a few integrated circuits. Here this post gives information about the advantages and disadvantages of the microprocessor to better understand this topic.

Advantages of a microprocessor:
  • The microprocessor is that these are general purpose electronics processing devices which can be programmed to execute a number of tasks
  • Compact size
  • High speed
  • Low power consumption
  • It is portable
  • It is very reliable
  • Less heat generation
  • The microprocessor is very versatile
  • The microprocessor is its speed, which is measured in basically Hertz. For instance, a microprocessor with a measured speed 3 GHz, shortly GHz is capable of performing 3 billion tasks per second
  • The microprocessor is that it can quickly move data between the various memory location
Disadvantages of a microprocessor:
  • The main disadvantages are it's overheating physically
  • It is only based on machine language
  • The overall cost is high
  • The large size of PCB is required for assembling all components
  • The physical size of the product is big
  • Overall product design requires more time
  • A discrete component is used, the system is not reliable
  • Most of the microprocessor does not support floating point operations
  • The processor  has a limitation on the size of data
  • This processor should not contact with the other external devices
  • The microprocessor does not have any internal peripheral like ROM, RAM and other I/O devices

Advantages and disadvantages of digital multimeter

A digital multimeter is a device which can provide combined functionality of ammeter, ohmmeter, ammeter. It is commonly known as DMM. DMM is Most widely used due to its small size, price, and ease in case of operation. Here this post gives information about the advantages and disadvantages to better understand this topic.

Advantages of digital multimeter:
  • The output can be interfaced with external equipment
  • They are having high input impedance, so there is no loading effect in multimeter
  • They are available in smaller sizes or compact
  • An unambiguous reading is obtained
  • There are more accurate  than an analog multimeter 
  • Portable size makes it is easy to carry anywhere
  • They have a very high input impedance
  • They cause less meter loading effects on the circuit being tested
  • Some advanced digital multimeter has a microprocessor and can store the reading for further processing
  • They reduce reading and interpolation errors
  • Unlike analog multimeter, zero adjustments is not required
  • It can be used for measurement AC and DC both quantity
  • It can be used for measurement of various parameters such as resistance, voltage,  and current, etc
  • It has a sensitivity of 20 kilo-ohms/ V which is fairly high
  • Measurement of quanties with different range can be possible
  • It is very simple to use unlike analog multimeter as a result are displayed in value of like numeric value directly and user need not have read manually from the scale
  • The auto polarity function can prevent problems from connecting the meter to test circuit with the wrong polarity
  • Parallax errors are eliminated. If the pointer of an analog
  • Digital multimeter displays have no moving parts. This makes them free from wear and shock failures
  • With the advent of ICs, the size, cost and power requirement of digital multimeters has been drastically reduced
  • DMMs can be used in testing continuity, capacitors, diodes, and transistors. A more advanced digital multimeter can also measure the frequency
  • The digital output is suitable for further processing or reading and can be useful in a rapidly increasing range of computer controlled applications
  • Digital multimeter has an LCD display to show an accurate reading
  • There is digital multimeter which provides auto range feature. In this type of meter, the user need not have to worry about setting the range of measurement. It is done automatically  by the meter itself
Disadvantages of digital multimeter:
  • It is more expensive than the analog type
  • The LCD display depends on a battery or an applying external power source. When the battery is  too much low, the display will be dim, making it difficult to read the result
  • There is a voltage limitation. If it increased beyond the limit, the meter will be damaged
  • It should be used as per manufacturer range and as per category rating. Failing to do this will cause damage to the equipment and also cause personal injury
  • In case of fluctuations or transients, it can record an error
  • Warming of the meter during its use can change its properties leading to errors in the measured value
  • The digital nature makes it unsuitable for adjusting the  tuning circuits or in the peaking tunable responses
  • The A/D converter has a limitation on word length which can cause quantization noise giving rise to an error in the measured value

Difference between resistance and resistivity

Resistance and resistivity are both concepts for electrical engineering. Resistance gives the ratio of potential difference to current across a conductor at a given time, whereas resistivity is the ratio of an electric field to current density for a material at a specific temperature. Here this post gives the difference between resistance and resistivity to better understand this topic.

Definition:

Resistance: Resistance is the physical property of a substance because of which it processes the flow of current.  Example - electrons
Resistivity: Resistivity is the physical property of a particular substance which is having particular dimensions.

The basic key difference between resistance and resistivity are given below:
  • Resistance is directly proportional to the length and temperature while it is inversely proportional to the cross-sectional area of the material while resistivity is only proportional to the nature and temperature of the particular material.
  • The symbol of resistance of  R, while the symbol of resistivity of ρ.  
  • The SI unit of resistance in Ohms, The SI unit of resistivity is ohms-meter.
  • The resistance is the property of the material which obstructs the flow of current, whereas the resistivity gives the resistance of the material which has a fixed dimension.
  • The resistance of the conductor depends on its length and area of cross sections, The resistivity of the conductor does not depend on its length and area of cross-section. It depends on the nature and temperature of the material
  • The property of resistance is used in several places like heaters, fuses, sensors, etc, Electrical resistivity measurement is used as a quality control test for calcareous soil.
  • R=V/I or R = ρ (L/A),  ρ = (R*A) / L . V=Voltage, I=Current, ρ=Resistivity, A= Cross sectional area, L=Lengh, R = Resistance.