CORRELATION 2 - EST 81-100

• The transistor with the lowest noise figure in the microwave region is a MESFET
• Transit-time noise becomes of great importance at frequencies
• The solar cycle repeats the period of great electrical disturbance approximately every 11 years
• The square of the thermal noise voltage generated by a resistor is proportional to:

  • Its resistance
  • Its temperature
  • The bandwidth over which it is measured
• Noise occurring in the presence of signal resulting from a mismatch between the exact value of an analog signal and the closest available quantizing step in a digital coder is called quantizing noise
• Impulse noise consists of irregular pulses of short duration and relatively high amplitude
• Crosstalk is noise that occurs via capacitive or inductive coupling in a cable
• Sources of impulse noise induced in communication channels include:

  • Erroneous digital coding bit caused by an error on a transmission facility
  • Transients due to relay operation
  • Crosstalk from DC signaling systems
• Crosstalk due to incomplete suppression of sidebands or intermodulation of frequency-multiplexed channels is classified as miscellaneous noise
• A psophometer is a device that measures the internal open circuit voltage of an equivalent noise generator with an impedance of 600Ω delivering noise power to a 600 Ω load
• External noise originating outside the solar system is known as cosmic noise
• Noise whose source is within the solar system is called solar noise
• Noise density refers to the total noise power present in a 1-Hz bandwidth
• Increased channel bandwidth is not a way of minimizing or eliminating noise
• The primary cause of atmospheric noise is lightning
• Noise coming from the sun and stars is referred to as space noise
• Thunderstorms are the major cause of atmospheric or static noise
• MESFET is a low noise transistor commonly used at microwave frequencies