electrical length การใช้

• electrical length of the antenna at the wavelength in use.
• The feedpoint impedance of a dipole antenna is very sensitive to its electrical length.
• This design is limited because the electrical length of the coupler will only be ? / 4 at one specific frequency.
• Then it may be said that the coil has lengthened the antenna to achieve an electrical length of 2.5 meters.
• The loading provided by the helix allows the antenna to be physically shorter than its electrical length of a quarter-wavelength.
• In general, although their effective electrical length is longer, the fractal element antennas are themselves physically smaller, again due to this reactive loading.
• The real ( resistive ) and imaginary ( reactive ) components of that impedance, as a function of electrical length, are shown in the accompanying graph.
• In the electrical domain, a transmission line, a basic distributed element component, can be included in the model with the introduction of the additional element of electrical length.
• Where there is insufficient board space to extend an antenna to the full required length, the antenna may be meandered to reduce its height while retaining its designed electrical length.
• Electrical length can also be expressed as the angle units . \ theta, the mathematical symbol for an angle variable, is used as the symbol for electrical length when expressed as an angle.
• Electrical length can also be expressed as the angle units . \ theta, the mathematical symbol for an angle variable, is used as the symbol for electrical length when expressed as an angle.
• In free space, this frequency corresponds to a wavelength of ? 0 = 10m, so a delay of . 25? would require an " electrical length " of 2.5 m.
• By charging the transmission line and then discharging it into a resistive load, a rectangular pulse equal in length to twice the electrical length of the line can be obtained, although with half the voltage.
• Antennas longer than a quarter wavelength have patterns consisting of several conical " lobes "; with radiation maxima at several elevation angles; the longer the electrical length of the antenna, the more lobes the pattern has.
• Cray addressed the problem of skew by ensuring that every signal path in his later computers was the same electrical length, so that values that were to be acted upon at a particular time were indeed all valid values.
• Also, when the information being transmitted has frequency components whose wavelength is a significant fraction of the electrical length of the feed line, distortion of the transmitted information will occur if there are standing waves on the line.
• For example, a monopole antenna such as a metal rod fed at one end, will be resonant when its electrical length is equal to a quarter wavelength, " ? " / 4, of the frequency used.
• This is identical to a 1 : 1 SWR . This condition ( " Z " load = " Z " 0 ) also means that the load seen by the source is independent of the transmission line's electrical length.
• In microwave and radio-frequency engineering, a "'stub "'or "'resonant stub "'is a length of transmission line or inductive, depending on the electrical length of the stub, and on whether it is open or short circuit.
• Since the electrical length of a physical segment of transmission line depends on the signal frequency, violation of this condition means that the impedance seen by the source through the transmission line becomes a function of frequency ( especially if the line is long ), even if " Z " load is frequency-independent.