Intermodulation Distortions

If you apply a signal of 61.25 MHz to an amplifier, at what frequency will a harmonic distortions appear?

122.5 mhz it doubles

If the output of an amplifier is changed by 1 dB the third order distortions change by ___ dBc.

2

Express the composite second order beat distortions for the following channels: Channel A is 55.25 MHz Channel B is 175.25 MHz. (Choose 2)

230.5 MHz 120 MHz

Express the composite triple beat distortion: (Choose 2)

2xF1 - F2 F2-F1+F3

If you change the output level of an amplifier from 44 dBmV to 48 dBmV, how much will the CSO performance change?

4 dbc CSO in dBc decreases by 1 dB for each 1 dB increase in output level. For example, if a device is specified for a CSO of 68 dBc at a nominal operating level of 46 dBmV per channel, the CSO performance will be reduced to 66 dBc if the output level is increased by 2 dB to 48 dBmV per channel.

If you change the output level of an amplifier from 44 dBmV to 48 dBmV, how much will the CTB performance change?

8 dbc For each 1 dB increase in carrier level, CTB decreases by 2 dB. For example, if an amplifier is specified for a CTB of 65 dBc at an output level of 46 dBmV, the CTB will become 61 dBc at an output level of 48 dBmV.

discrete second order dso

Combining of two frequencies to produce a third frequency.

discrete third order dto

The source of CTB. When three signals have mixed in a non-linear device to produce a distorted signal.

composite second order cso

The total effect of all DSO products within one channel.

composite triple beat ctb

The total effect of all third order products within one channel.

cross modulation distortion

The transferring of signal information (intelligence) from one carrier to another.

One source of electrical noise is thermal noise

Thermal noise is broadband in nature. It is caused by the random motion of electrons in electrical circuits. All electrical components, even passive components such as resistor contribute to thermal noise.

Distortion manifests as extra signals called ___.

beats

Identify the units that indicate the power relative to the power of the main carrier frequency.

dBc

Optical links can not cause distortions.

false

Impulse Noise is caused by the random motion of electrons.

false Impulse noise occurs in brief bursts or impulses. Although impulse noise is brief in time it is very broadband in frequency. Impulse noise is generally created by sources outside of the coaxial or HFC network and leaks into the network as ingress.

Are intermodulation distortions input or output related?

output

Which of the following is a source of noise caused by random motion of electrons?

thermal noise

For every dB increase in the carrier power, XMOD worsens by 2 dB.

true

True or False: Intermodulation (CSO, CTB, XMoD) from an amplifier is the result of its nonlinear operation.

true

True or False: Using a spectrum analyzer, cross modulation would be found in the 15.75 kHz (approx.) video sidebands.

true