公开(公告)号：US3633129A

公开(公告)日：1972-01-04

申请号：US3633129D

申请日：1970-10-12

Applicant: BELL TELEPHONE LABOR INC

Inventor： KAO CHIH-YU ,  KURTH CARL FERDINAND ,  MACLEAN RODERICK CAMPBELL

IPC: H04B3/14 ,  H04B3/04

CPC classification number: H04B3/141

Abstract: An equalizer of a coaxial transmission system is automatically adjusted by applying a sweep signal to the equalizer and comparing the output of the equalizer with a predetermined reference signal to develop an error signal. The output signal of the equalizer is simultaneously converted into a train of pulses and applied to a frequency selector which generates signals upon the occurrence of predetermined frequencies in the equalizer output signal. In response to these generated signals, predetermined intervals of the error signal are integrated, converted to digital signals, and applied to the proper ''''memory'''' of the equalizer.

Abstract translation: 通过向均衡器施加扫描信号并且将均衡器的输出与预定的参考信号进行比较以产生误差信号来自动调整同轴传输系统的均衡器。 均衡器的输出信号同时转换为脉冲序列，并施加到在均衡器输出信号中发生预定频率时产生信号的频率选择器。 响应于这些产生的信号，误差信号的预定间隔被积分，转换成数字信号，并被施加到均衡器的适当的“存储器”。

公开(公告)号：US3904978A

公开(公告)日：1975-09-09

申请号：US49563974

申请日：1974-08-08

Applicant: BELL TELEPHONE LABOR INC

Inventor： DANIELS RICHARD WILLIAM ,  KURTH CARL FERDINAND

IPC: H03H11/12 ,  H03F1/36

CPC classification number: H03H11/1295

Abstract: An active filter having a predetermined fourth-order transfer function is realized by employing a single gain unit, for example, a differential amplifier, in conjunction with two passive resistor-capacitor (RC) circuits. The RC circuits have pole-zero pairs which are widely separated in frequency. Consequently, each RC circuit does not cause appreciable distortion in the attenuation characteristic of the filter in the frequency band in which the other RC circuit is affecting the filter attenuation characteristic.

Abstract translation: 具有预定的四阶传递函数的有源滤波器通过采用单个增益单元（例如，差分放大器）结合两个无源电阻 - 电容（RC）电路实现。 RC电路具有极零对，在频率上分开。 因此，每个RC电路在其他RC电路影响滤波器衰减特性的频带中不会引起滤波器的衰减特性的明显失真。

公开(公告)号：US3676598A

公开(公告)日：1972-07-11

申请号：US3676598D

申请日：1970-06-08

Applicant: BELL TELEPHONE LABOR INC

Inventor： KURTH CARL FERDINAND

IPC: H04J1/04 ,  H04J1/05 ,  H04J1/02

CPC classification number: H04J1/04 ,  H04J1/05

Abstract: A frequency division multiplex single-sideband modulation system uses a multiplexed digital filter, the passband of which is sequentially shifted from one multiplexed channel to another in synchronization with an input time division multiplex commutator and a frequency multiplexer modulator. In other embodiments of the invention selected spectral components are advantageously emphasized by signal processing techniques employing repetitive sampling prior to modulation and filtering.