Patent EA-000732-B1 (EA)
Title: Method of transmitting and receiving data
Inventor: BRYZGALOV A P
IPC: H04B1/707
Filed: 1997-02-26
Abstract: 1. The method for the transmission and reception of information consists of the following: for transmission form a message signal by modulating the message to be transmitted, form a wide-band carrier signal, branch the carrier signal into two components and by multiplying one of the components with the message signal form an information signal for transmission and from the other component form a reference signal for transmission; combine the generated information and reference signals, amplify and radiate; at reception transform the received signal into an electrical signal, amplify and form two signals, multiply these and filter the result of this multiplication, extract the message signal, demodulate and recover the message; with the following distinguishing features: for said carrier signal, use a wide-band signal whose bandwidth can approach the minimum frequency of its spectrum; for said information and reference signals, in order that they can overlap in terms of time and frequency, use a subcarrier frequency for the message signal and / or a time delay in one of the components of the carrier signal after branching; for said subcarrier frequency choose a frequency greater than the bandwidth of the message signal, but not more than a frequency interval of the emitted bandwidth for which throughout the communication path the amplitude - frequency characteristics are relatively constant and the frequency - phase characteristics relatively linear; for said time delay, choose a delay not less than the value of the inverse of the bandwidth of the spectrum of the carrier signal, but not more than the interval during which the path remains stationary at reception and after filtering and amplifying, branch the received signal into two signals, if a delay was applied in the transmitter, then delay one of the signals by the same amount and after multiplication of the two signals filter the output on the frequency and band of the message signal. 2. The method as described in claim, in which as a carrier signal a continuous noise signal, for which there may be imposed limits on amplitude, with the required bandwidth, is used. 3. The method as described in claims 1 and 2, in which for the transmission of N messages form N message signals whose subcarrier frequencies are sufficiently separated such that their spectra do not overlap, carry out additional branching of the carrier signal for the purpose of multiplication with each of the message signals thus forming individual information signals, combine to form the resulting information signal for transmission, and at reception and after multiplication of the two signals carry out parallel filtration for all the message signals. 4. The method described in claim 3, in which for the formation of individual information signals, besides employing subcarrier frequencies, introduce fixed delays to one of the two components of the carrier signal after branching with the difference in delays not less than the value of the inverse of the bandwidth of the spectrum of the carrier signal, by allocating to each message to be transmitted its individual combination of subcarrier frequency i and / or delay j form individual information signals; by combining these information signals form the resulting information signal for transmission and where the individual information signals have different delays the subcarrier frequencies of their message signals can be equal; at reception and after branching of the received and filtered and amplified signal, for each delay as applied in the transmitter, delay one signal after branching by the same amount and multiply with other signal, and after each multiplication filter to recover the message signals.