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Amplifiers Classification Of Amplifiers

Amplifiers Classification of amplifiers

The amplifier is one of the most important devices in the cable TV system, which is widely used in the front-end, trunk transmission and user distribution network. Amplifier in the carrier to noise ratio and is the main purpose of nonlinear distortion index under the premise of as much as possible to enlarge low level signal at the input, to compensate for the transfer of the coaxial cable of the loss and to provide users with the appropriate signal level. The performance of the amplifier, the input of the amplifier and the output value of the output, directly affect the transmission quality of the system. Different types of amplifier and its performance, price difference is very big, the different parts and different usage should choose different types of amplifier, know the performance of the amplifier, parameters and applications is one of the keys to learn cable TV.

One, the classification of amplifier 1, according to the working frequency of amplifier classification: 550 m and 750 m, 860 m 2, according to use classification: the front amplifier, trunk amplifier, circuit amplifier, distribution amplifier, building 3, according to the internal amplifier amplifier to gain, control mode of the slope classification: (1) the manual gain control (MGC) and manual slope control (MSC) amplifier; (2) automatic gain control (AGC) amplifier; (3) automatic level control (ALC) amplifier. (1) push pull (PP) amplifier; (2) power multiplier (PHD) amplifier; (1) one-way (forward) amplifier; (2) the bi-directional amplifier Second, the main technical parameters of 1, the gain of the amplifier (1) the full gain, the internal amplifier equalizer, attenuator are transferred to the minimum (0 db attenuation and balanced) amplifier gain at the highest frequency; (2) work gain, in the nominal input level, the attenuation of the amplifier's internal attenuator and the equalizer's average measurements are included, and the amplifiers can be obtained at the maximum frequency. 2. Working band: frequency range defined by full gain. 3. Flat degree (unflatness) : the maximum and lowest frequency response level of the broadband amplifier in the working band is the total deviation of the level of the flat of both. Plus or minus 0.75 dB. 4. Number of work channels: according to the working bandwidth of the amplifier, the number of test channels entered by the manufacturer. All other technical parameters are measured at the same time the channel is entered. 5. Nominal work input level: in the work gain and the slope, meet the central point in the input level of the amplifier's performance parameters. 6, nominal output level: in the working gain and slope, double the recommended level said inclined channel (high/low channel) output level, the total level, the highest frequency output level. 7. Signal communication ratio: the ratio of signal and parasitic ampliation to peak power communication peak in carrier signal. 8. Cross modulation ratio (CM) : the frequency modulation ratio of the amplifier in nominal working channel number and nominal work output power. 9. Combination of the second distortion ratio (CSO) : the amplifier is in nominal working channel number, nominal work output the normal combination of the second loss ratio. 10. Combination of three differential beats (CTB) : the amplifier is rated on the number of working channels and the nominal output of the output of the work is compared to three times. When the number of actual input channels of the amplifier is not equal to the number of the number of working channels in the manufacturer's test, CM, CSO and CTB should be corrected. When the actual output level of the amplifier is not equal to the nominal output, CM, CSO and CTB should also be corrected. 11. Noise factor: indicators of noise generated within the amplifier. 12. Maximum output level: the maximum output level is the maximum output level of the amplifier when the ratio is 60dB (while entering two test channels at the same time). 13. (echo value) : in the prescribed test conditions, the system in which the measurement is measured is delayed by the original signal and the same interference signal as the original signal.