NCTI ROC II BOOK II FINAL Test 1

When pressure testing a drop system to check for leakage, What must be done before applying the test signal? - The technician must isolate the drop system from the hybrid fiber/coax (HFC) network by disconnecting the drop at the distribution tap. Why do some leakage detection systems utilize a leakage carrier modulated with a tagging signal? - To avoid false detection of leaks. When all three sections of a pulse code modulator (PCM) are combined, what function can be performed? - · As an analog-to-digital converter (ADC) What prevents the subcarriers in orthogonal frequency division multiplexing (OFDM) from interfering with each other? - · The peak power of each subcarrier aligns with the minimum power of the adjacent subcarrier. What two significant signals go into the mixer to create the intermediate frequency (IF)? - · The RF signal frequency at the output of the front-end filter and the local oscillator (LO) signal. Which class of amplifier efficiency approaches, but never achieves, 100%? - · Class D amplifier. What is the output waveform coming from a ferroresonant power supply? - · A quasi-square wave. What instrument should be used to accurately measure the output voltage of a ferroresonant power supply? - · A true root mean square (RMS) digital multimeter (DMM) What could a light dimmer with a silicon controlled rectifier (SCR) create in a customer premises? - · Radio frequency interference (RFI). What is a characteristic of a bipolar junction transistor (BJT) common emitter configuration? - · The output signal is taken from the emitter. What is done to an operational amplifier (op amp) to create a low-pass filter circuit? - · A capacitor is placed in parallel with the feedback resistor that is connected to the op amp inverting input (-).