Design And Implementation Of TADIL-A's Demodulation Solutions In High Frequency Channel

TADIL-A (tactical digital information link A) signal is a typical multi-carrier signal in high frequency channel. It is a common tactical digital information link in common use in US military and NATO organizations. It is mainly in use of exchange the data of electron battle, track line of over the air, surface and under of the water, it takes the mission of the data's exchange between multi-warship and multi-aircraft face to face. As a part of network central war of foreign army, TADIL-A will place an important role in modern information based war.Nowadays, TADIL-A's used a lot in military high frequency communication. But there isn't mature product of demodulation equipment of it. So as we deeply study this special multi-tone modulated signal, we exhibit the software demodulation method based on soundcard which solve the receipt and demodulation matter of this signal.With the "Design and implementation of the TADIL-A's demodulation solutions in high frequency channel" as research focus, this paper mainly finished the following work:1. Analyses the fading characteristic of HF channel, introduces the typical modulation technique of high frequency channel and the typical usage and development actuality of multi modulation technique.2. Introduces the communication regulation and working style of TADIL-A, analyses the feasibility of reception and demodulation of this signal.3. Introduces the principle of demodulation of digital modulated signal and exhibits the integer demodulation algorithmic of short robust signal from multi-channel and multi-carrier modulated signal.4. Researches the basic knowledge and principle of signal detection, designs two ways in TADIL-A signal's detection as energy detection algorithm and FFT transform algorithm.5. Researches the estimation methods of the subcarriers and brings the algorithm of emendating the carrier shift based on the Hilbert transform and the algorithm of getting the synchronous information based on the principle of orthogonal suited of rift value, and last the topic realizes the demodulation of TADIL-A signal.6. Combines with the real signal, designs the reception and software demodulation module based on soundcard.