SU82709A1 - Modulating device - Google Patents

Description

A modulating device is proposed that doubles the number of communication channels.

In communication technology, systems and apparatus are known that allow one to transmit one sideband or both sidebands without a carrier frequency, with carrier frequency being recovered using a separate generator at the receiving point.

The use of simultaneous amplitude and phase or frequency modulation is known.

In the described device, an intermediate frequency is applied, which is modulated so that the positive frequency is modulated from one low-frequency channel, and the negative half-period from the other.

The device makes it possible to eliminate filters that are usually used for channel separation and at the same time have unstable generators of both carrier and intermediate frequencies, since their stability does not affect the quality of channel separation.

FIG. 1 shows a skeletal diagram of a radio channel; in fig. 2 shows a polar modulator circuit with an intermediate frequency generator; in fig. 3-circuit polar detector.

When transmitting by radio (Fig. 1), the low frequency channels are modulated and the intermediate frequency modulates the high frequency carrier in one of the usual ways.

When transmitting by wire (in the absence of a high-frequency channel on this line), the second modulation is eliminated.

The intermediate frequency generator (Fig. 2) feeds the heterodyne grids of two modulator lamps (modulators I and II) operating on a push-pull circuit. The low frequency is applied to the control grids of these lamps. The frequency from the first channel / is low to the grid of the first lamp, and the frequency from the second channel to the grid of the second lamp is low.

As a result, the positive half-periods are modulated from one low-frequency channel, and the negative from the second one. Modulated in this way, the intermediate frequency goes directly to the line, or modulates a high-frequency carrier (output) generator.

At the receiving point, a polar detector is used (Fig. 3), which consists of one dual diode. From the line or from the receiver output, the low frequency signal enters the polar detector, where one channel (positive) is detected by one half of the diode and the other channel (negative) by the other half, and channel separation is carried out without any filters.

The subject matter of the invention

A modulating device that doubles the number of communication channels, characterized by the use of an intermediate frequency modulated so that a positive half-cycle is modulated from one low frequency channel, and a negative half-cycle from another.

The generator is a moan. frequencies

I channel

05ytny

Polar nepedam -: UK modulator

Ekanal

1 channel / 1

Zhkpnpl

LALDA

Cuto frequency prom generator

Modulator