The maximum voltage that the single output tube bears when it is cut off is ()
B.8 times the power supply voltage
[Single] color TV shows serious crawling phenomenon, and its fault location is ()
A. Ultrasonic delay line
B. Matrix circuit
C. Phase locked circuit
D. Synchronous detection circuit
Answer: A
[Single] Recording machine magnetic head has various magnetic bias methods, The best effect is ()
A. DC bias
B. AC bias
C. Constant magnetic bias
D. No bias
Answer: Among the following indicators, () has no effect on the sound quality of the audio signal
A. Signal to Noise Ratio
B. Distortion
C. Signal Level
D. Harmonics
Answer: C
If the working voltage of a single audio amplifier is constant, in order to increase the output power, in addition to improving the amplifier circuit, the specifications of the speaker should also be improved as follows ()
A. Impedance reduction, rated power increase
When a single imaging tube is working, the radiation () from the outside is the most harmful to the human body.
, So the picture tube needs to be blocked with lead containing glass to reduce leakage A. InfraredB. Ultraviolet
C. X-rays
D. Other electromagnetic waves
Answer: C
[Single] relative to CRT, The drawbacks of LCD displays are ()
A. High power consumption
B. Narrow viewing angle
C. Low resolution
D. Severe electromagnetic radiation
Answer: B
The main function of a single detector is to pick up ()
A. Intermediate frequency signal
B. High frequency signal
C. DC signal
D. Original modulation signal
Answer: D
When using a single transistor as a switch, Working state is in ()
A. Cutoff zone
B. Amplification zone
C. Saturation zone
D. Cutoff zone and saturation zone
Answer: D
The reason for the malfunction of the accompanying sound interference image is ()
A. Poor sound surface filter
B. AFT phase shift circuit misalignment
C. The 6.5MHz carrier frequency of the second accompanying sound intermediate frequency is inaccurate
D.6.5MHz absorption circuit misalignment
Answer: D
[Single] PAL system The frequency of the progressive reverse switch signal is ()
B.7800HZ
The components that can form an intermediate frequency characteristic curve in one go are ()
A.LC filter
B. crystal oscillator
C. surface acoustic wave filter
D. field effect device
Answer: C
The frequency of the intermediate frequency signal in the image of a single TV receiver is ()
D.38MHz
The tape speed of a single video recorder depends on ()
A. The speed of the magnetic drum
B. The speed of the main shaft
C. The speed of the take-up pulley
D. The speed of the take-up pulley
Answer: A
[Single] The common feature of PAL and NTSC color TV systems is ()
A. Interlaced scanning
B. 50 fields per second
C. 625 lines per frame
D. The modulation method for chromaticity signals is the same
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