Study Of The Key Technologies About The Measure And Control Signal Digital Processing

As an important part of the space probe & missile system, the TT&C system plays an importance role in the telecontrol and telemetry of these special targets. So far in our country, the signal form of TT&C has been transferred from none spread-spectrum modality to spread-spectrum one, the processing manner on intermediate frequency has been developed from analog circuit or analog & digital mixed circuit to fully digital circuit, the functions implemented has been changed from individual & separated mode to integrated base-band processing one, and the form of equipments has been transferred from tied equipment to universal equipment. Under this background, this paper makes a deep research on the pivotal technology of signal processing on the TT&C, in order to realize highly reliable, strongly universal, less complicated and more secure equipment for telemetry and telecontrol.First of all, the rapid acquisition method of short term and burst DSS (direct spread sequence) has been investigated. In the TDMA-CDMA-mixed communication system, the performance of PN sequences synchronization has great influence on the system performance. The paper presents an improved structure of two-dimension rapid acquisition of PN sequences based on carrier frequency and PN sequence phase, and deduces the approximate expressions of the system performance for this structure. Compared with the undeveloped algorithm, this structure has serial advantages, such as short acquisition time, low complexity, high accuracy, wide agility, and small residual frequency under wide SNR (signal-to-noise rate) dynamic range.Secondly, rapid acquisition of the weak DSS signal with high frequency offset has been studied. A rapid acquisition structure is put forward when the field of synchronization exists, and its performance expressions for various parameters are deduced. The influence of these parameters and asynchronous PN sequences on the performance on the usual acquisition structure is analyzed. And an improved arithmetic and its performance are put forward. Simultaneously, a rapid acquisition structure for the situation without the field of synchronization and its performance expressions are put forward. Based on the expression of divided match filter's performance, a comparison is made between the developed algorithm and the undeveloped one.And then, problems on the rapid recognition and acquisition of dual mode signal are investigated. A rapid acquisition structure and performance evaluation index of the recognition and acquisition of dual mode signal are brought forward. And also a detail expression is deduced. The structure above is then compared with the usual structures. Finally, the full digital reconstruction of coherent signal is investigated. The algorithm is proposed for the situation with unknown side-tone frequency and modulation parameters, which performance expression is also given out. At the same time, it is compared with the current implement forms. Under the current hardware level, the influence of clocks on the performance of the carrier and side-tone recovery is analyzed when the low capability frequency source is used as the clock source of the digital devices. And the analyzing results are testified by the numbers.