Method and apparatus for monitoring and controlling gain compression in transmitted signal

用于监视并控制卫星转发器放大器(108)的工作点的方法和装置。地面卫星(100)处接收到的时域信号被数字采样。计算接收信号的直方图并绘成图表。低压制程度下，直方图一般表现为近似钟形曲线。较高压制程度下，钟形曲线变得失真。通过把获得的直方图与模板直方图相关，可以确定压制量。该压制量指示了转发器放大器(108)的工作点。根据需要，可以调整由卫星所使用的发送功率电平，以确保放大器工作在期望的压制程度。本发明优于现有技术的优点在于，可以更准确地确定转发器放大器的工作点。可以更精确地调整工作点。 A method and apparatus for monitoring and controlling the operating point of a satellite transponder amplifier. In one aspect of the invention, a time domain signal received at a ground station is digitally sampled. Then, a histogram of the received signal is computed. To form the histogram, the digital samples are categorized according to which of a plurality of amplitude ranges each sample falls within. When plotted as a graph, the number of occurrences within each amplitude range forms the histogram. Under low compression levels, the histogram generally appears as an approximately bell-shaped curve. However, under higher compression levels, the bell-shaped curve becomes distorted. By correlating the acquired histogram to a template histogram, an amount of compression can be determined. This amount of compression indicates the operating point of the transponder amplifiers. If desired, the transmission power levels used by the satellite can be adjusted to ensure that the amplifiers operate at desired levels of compression. The invention has an advantage over prior techniques in that the operating point of the transponder amplifiers can be more accurately determined. As such, the operating point can be more precisely adjusted.