Controllable automatic gain controlling circuit for cable television network

Abstract

This invention relates to a controllable automatic gain control circuit used in wire TV network. A RF input signal outputs a master signal and generates a RF output branch signal via a voltage control attenuator, a RF amplifying module and a branch device, then the RF branch signal is connected with a RF test module, its output is connected to a single-chip processor with an A / D and D / A conversion function module, the control signal output after PID algorithm process to the input signal via the single-chip processor is connected to the voltage control attenuator to form an automatic gain control loop.

Description

technical field [0001] The invention relates to an automatic gain control circuit for a cable television network, in particular to a controllable automatic gain control circuit for a cable television network. Background technique [0002] In most transmission equipment, the stability of the signal transmitted from the front end of the front-end hybrid transmission system (HFC) is poor. In addition, factors such as aging attenuation and temperature fluctuation of the cable network and optical fiber network cause large signal fluctuations in the network, which often exceed the adjustment of the AGC circuit. Range, resulting in imbalance phenomenon, can not play the role of automatic gain control. On the other hand, sudden noise often occurs in the channel of backhaul reception, which requires network managers or equipment to adjust the channel gain in time to eliminate the adverse effects of noise. [0003] In the prior art, there is a radio frequency automatic gain control (...

AI Technical Summary

Problems solved by technology

[0005] To sum up the above, the existing AGC circuit does not have a manageable function, the output level of the circuit cannot be set through the network, the required stabilization time is long, and the stability is poor

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