Application of the isomorphic emphasis to spectrum scrambling encryption over analog speech channels

In mobile communication, there is the danger that the content of communication may be intercepted. The encryption which protects confidentiality is studied from various approaches. The existing method, which merely adds an encryption function, increases the effective modulation index above the level without encryption and brings on a spread of radio frequency bandwidth. It has been shown that the effective modulation index can be maintained, when isomorphic emphasis applies to spectrum inversion encryption. It is established that isomorphic emphasis maintains this feature, even if it applies to an arbitrary spectrum scramble pattern. This circuitry configuration is the most economical when introduced into PM transmission