TH23791A - Methods and equipment for the encryption and decryption of speech in audio transmission. - Google Patents

Abstract

In the case of this invention based method For voice encryption and decryption in Transmitting audio signals, including equipment using the said method Real audio signal that is digital The kidney is converted through a complex filtration that is more suitable to pass. Hilbert filtering It is a complex signal which is taken to reduce the sample wash rate. The band width of each complex filter inserted. Corresponding to the wash rate, for example, the overlap signal obtained from This is modulated phase. By means of the signal code produced By a random number generator and added to the pirate signal Which is modulated the same phase in random distribution to produce a useful signal that is Encrypt to be sent Useful signals are sent in Characteristics are sequential with Introductory articles which are used for Useful synchronization and equalization at the receiver end, in the other hand the receiver end. Rhythm The clock signal for a modulated phased signal that is produced at the receiver end is forced. And in other words The equalizer coefficient for the equalizer (51) at the receiver end was likewise calculated from the digitized received signal after the complex filtering and reduction. Seizure rate Consistently during the introductory article recognition phase Where the decryption phase A useful signal is initiated at that location. A useful signal being transmitted is encrypted. Secret is separated from Its phase-modulated pyrotechnic signal is superimposed at the transmitter end by association with a synchronized pile signal produced at the receiver end. And therefore, the modulated phase-received encrypted digital speech signal was subsequently broken down by a coded signal path produced at the receiving end and clocked control by the introductory article. In comparison with the well-known speech encryption methods, the invention has advantages in Stability in the examination at Very good associated with high speech intelligibility and speech recognition. That is good, although it is consistent with Defined transmission band width that can be used in analog radio networks and in telephone applications.

Claims (1)

1. A method for voice encryption and decryption in audio transmission is available. Unique feature that At the transmitting end - the digital audio signal c (v) is converted by means of Of one (30) complex input filter with a bar width Which corresponds to the strip width of the sending channel It is a complex signal x (n), modulated phase by a code signal path (Zs (n)), which is controlled by a pseudo-random number - the modulated sound signal phase (y (n)) is modulated. Tag: