Method and apparatus for measuring the group delay characteristics of a transmission path
US3970926A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 21, 1975 |
| Grant date | Jul 20, 1976 |
| Priority date | — |
| Expiry date | Feb 21, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B3/462
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A method and an apparatus for measuring group delay characteristics of a transmission path is disclosed wherein a test signal is fed to the input of the transmission path and the test signal is amplitude modulated by a split frequency. The carrier frequency of the test signal is interchanged periodically between a measuring frequency and a standard reference frequency. The output measuring and reference signals of the transmission path are sensed by noting the positions in time of specified points of the envelope waveform that occur during the periods of the reference type signal and the measurement type signal. A digital pulse counter is provided for measuring a first time interval between a specified point during a period of a first type signal and a specified point during the subsequent period of the second type of signal, and for measuring a second time interval between the latter specified point and a specified point during the subsequent period of the first type of signal. The pulse counter is bidirectional and is reversed at the end of the first time interval. The counter state at the termination of counting represents the difference between the first and the second time int…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.