System Technician Conventional questions with correct answers

In a broadband cable network, where would a block convertor be most likely used? CORRECT ANSWER At the node What is sent with digital TV (DTV) transmissions that enables the receiver to synchronize with the sending device to decode and place the data in the correct sequence? CORRECT ANSWER A 27 MHz program clock reference (PCR) What risk is there in coupling the output of an oscillator to another circuit stage? CORRECT ANSWER The oscillator frequency could be changed (or pulled by) the next circuit stage. What is the primary difference between the Hartley and Colpitts oscillator circuits? CORRECT ANSWER The Colpitts oscillator uses capacitive feedback, and the Hartley uses inductive feedback. Which must be done to create an oscillator if the circuit transistor is in the common emitter configuration? CORRECT ANSWER Another 180-degree phase shift is necessary for positive feedback. When included in an oscillator circuit, what component enables the oscillator frequency to be controlled by voltage, hence, the voltage controlled oscillator (VCO)? CORRECT ANSWER A varactor (or varicap) diode. What is significant about how a crystal is cut with respect to the orientation of the quartz crystal lattice structure? CORRECT ANSWER The cut dictates pretty much all crystal characteristics, including frequency drift with temperature. Which resonant circuit mode of a crystal should be u