new ccna 200-125

new ccna 200-125.Because the term "frequency" appears quite often in wireless networks, it is important that you have a clear understanding of it. As discussed in Chapter 1, frequency determines how often a signal appears. It is the rate at which something happens or repeats itself over a certain period of time or a given sampling time or period. This statement that "frequency is how often a signal occurs" is not accurate. If you want to measure frequency, you need to observe it over a certain time period. Frequency is usually measured in seconds and is the rate at which the vibrations that form a wave occur.' Frequency can also exist in other forms of matter, such as in sound waves, or in electromagnetic fields, but also in radio waves and light waves.Since frequency is related to period, these important concepts below help to understand how frequency is measured. 1 period = lHz° The higher the frequency, the shorter the transmission distance. One waveform emerges in less than one second = 1 field. 10 times a second = 10Hz. 1 million times a second = lMHz. 1 billion times a second = lGHz. all of these values are very useful in learning about wireless networks.3. Amplitude ReviewIn a waveform, the vertical distance between the peak or trough and the equilibrium position is called the amplitude ( amplitude). There can be different amplitudes for the same wavelength and the same frequency. Amplitude is the amount or value of energy contained in a signal. Organizations like the FCC and the European Telecommunications Standards Institute (ETSI, EuropeanTelecommunicationsStandardsInstitute) regulate amplitude.Note: You can find a clear example of amplitude at http://id.mind.net/~zona/mstm/physics/waves/introduction/introductionWaves.html.4. What is effective omnidirectional radiated power? When an AP sends energy to a propagating antenna, there may be a cable between the two. A certain 24 Chapter 3 Wireless LAN RF Principles is lost in the cableof energy. To offset these losses, the antenna has to increase the gain, and so the energylevel is increased ( energylevel). The value of gain used depends on the type of antenna. Note that both the FCC and ETSI regulate the power emitted by the antenna. Finally, the EffectiveIsotropicRadiatedPower (EIRP) is the power that is ultimately sent out. EIRP is used to estimate the service area of a device.EIRPO is calculated using the following formulaEIRP = transmitter output power one cable loss + antenna gain