SU60477A1 - Two-way single-band telephony or telegraphy transmitter with the addition of phase-shifted oscillations and phase conversion of the audio frequency spectrum - Google Patents

Description

Naivy (Year of the two-way radio system from the point of view of ensuring high selectivity of radio reception and use of the frequency channel is a "two-time single-band system. In this system, one of the signals is transmitted by the lower sideband f - F, with common carrier frequency /.

In the single-band transmission scheme, but using the Shirex principle, a double conversion of sound frequencies can be used to shift the phase of the oscillations of these frequencies by 90 °. In such a system, to implement two single-band transmissions with a common carrier frequency, there is no need to completely duplicate the modulation scheme; it is enough to duplicate only the low-frequency part, leaving the high-frequency part of the transmitter; and common to both channels.

The essence of the proposed invention is that the same pair of modulating devices is used to receive both sidebands of a double single-subwoofer radio transmission.

The drawing shows a skeletal

transmitter circuitry performed

according to the invention.

Sonic (or tonal) frequencies

(FI, FZ) each of the telephone (or

telegraph channels / and 7 / are passed through bandpass NF filters, which limit the band in accordance with the frequency channel allocated for the station, and then are fed to the first PR Converter. The higher frequencies obtained by adding the frequencies jF and F2 with oscillations / "h of the auxiliary VG generator pass through the high-pass filters of the RF, which separate the total frequencies in and / hr -j-fa-. They are each fed to two pairs of converters PR for reverting to audio frequencies i n FZ- As a result, two voltages are obtained from each NC signal, with the elementary oscillations of all frequencies in one of the voltages being in the advancing phase by 90 ° with respect to the oscillations of the other voltage.

Thereafter, the oscillations of the two channels are added in such a way that the forward phase voltage of the channel / is added to the lagging voltage of channel II, and vice versa. The resulting double-signal voltages are fed through the low-pass filter filters to the inputs of the MY modulators. The modulators of the MF also receive the high-frequency voltage from the generator of the GHF (to one of the modulators through the phase shifter Phases).

245

At the output of one of the modulators, the voltages of the signals of the form UiSinQit + f / gCosy are added, and the high frequency voltage is 6 rSinoj,

At the input of the other modulator, the signal voltage (JiCosQit + U: sinQJ and the high frequency voltage UrCos t) is added.

As a result, at the output of modulators, oscillations of the sidebands of the form are obtained: () i +, sin Ov + 9, X,

where Ai is the amplitude of change of the modulator slope.

These vibrations are used after further amplifying the DT for transmission.

Subject invention

Two-way single-band telephony or telegraphy transmitter with the addition of phase-shifted oscillations and phase transformations of an audio frequency spectrum, characterized in that the same pair of modulating devices are used to receive both sidebands for transmitting two signals.