Analysis Of Digital Channel Transmission Error For The Timing Signal In Test Range

Timing system provides the standard time\frequency and displays all kinds of time in range test, allowing all the measuring and control system to work in according with reference time. With the development of digital communication, digital optical fiber and microwave transmitting technologies are applied widely in test range. However, the signal in the digital channel has distorted so that the general decoding method fails to generate the correct signals. This thesis introduces the architecture of the timing system, analyses and simulates the errors occurring in the channel transmission, and compares with actual signals, hence finding out that the errors result from the time relay and frequency characteristics of the channel. Accordingly, two methods of correcting the errors are proposed first.The first method is called signal transmission compensation, used to compensate timing signal in sending terminal by changing the B(AC) coding wave form of time reference system and adjusting the frequency and time field of advance to generate the correct signals out of channel. The software can be modified to apply this method.The second method, called channel balance, is to add equalizer on both sending and receiving terminals as to compensate the time delay and frequency characteristic.The calculator and analysis show that only one section of equalizer can correct the distortion of the signal in channel .The design of the equalizer made of separate elements is introduced and the test and validation are performed.Signal transmission compensation is generally complemented by manufacturer when new timing system is developed or modified. It requires that the sending waveform is adjusted to different channel Characteristics and the timing signal comforts to transmission channel, the timing system must has the capability to check channel characteristics at any moment. The channel balance can the carried out by transmission system manufactures, timing system manufactures and users. After balance is finished, it will only be used to the channel that works with it together. The characteristic of channel cannot satisfy the requirement of audio signal when one section of balancing equipment is used to the channel, this kind of channel can only transmit timing signal. Both methods can correct the errors which are created because timing signal is transmitted in digital channel. In some projects, it is cost effective when auto-detection and self-compensation and balance are achieved. The two methods can be selected in practical situations and have practical value and prospect.