SU144875A1 - Device to automatically maintain transmitter output power level - Google Patents

Description

In the applied automatic adjustment of the transmitter output power level during telephone operation on the same sideband with an incompletely suppressed carrier, the level of the high-frequency signal does not remain constant and varies in proportion to the level of the modulating frequency.

In the proposed device, in order to eliminate this drawback, a memory circuit is applied for storing the carrier frequency level at the moment of no modulation until the next pause in the modulation, and for adjusting the excitation amplitude over the intermediate frequency, diodes are connected in series to the splitter circuit connected to modulator input.

The drawing shows the block diagram of the device.

It consists of a microphone MK., A low frequency ULF amplifier, a CM mixer, which is supplied with a carrier frequency (and a low modulation frequency), automatic AGC gain control, intermediate frequency and high frequency amplifier amplifier, and UHF, a powerful MK cascade, a memory device of the charger, a relay P DC amplifier, UPT, AGC detector and relay control elements for EUR.

The principle of operation of the device is based on the use of the carrier residual (10-50%), the level of which, at the moments of no modulation, is stored for the duration of its operation. The time constant of the memory device must be significantly longer than the duration between two adjacent pauses (200-400 seconds), and the time for recharging the memory device that occurs during the moments of pauses (no modulation) must be significantly less than the pause time. The total charge of the storage capacity is determined by the transition time from reception to transmission.

With modulation, the automatic gain control AGC detector is disconnected from the storage device by a relay. When modulation is stopped, the voltage on the capacitor of the AGC detector should decrease to the carrier level. The frequency response of the detector is selected on the basis of the admissibility of high-frequency non-uniformity on the mesh, helmet, helmet, and under the action of AGC. The relay control circuit contains a resonant amplifier, the frequency of which is determined by the region of the highest signal-to-noise ratio at the output of the acoustic transducer, driven by strong noises. When choosing the highest signal-to-noise ratio, the ability of the relay to interfere with interference is greatly reduced. The DC voltage on the memory device determines the operating point of the lamp, in the anode circuit of which one or more diodes are connected. A constant current, a passage w; it through the dieads, changes the resistance in the divider circuit and thus, at the output of the divider, the high frequency voltage can be reduced ten times. The adjustment of the excitation voltage is made at an intermediate frequency. When the path gain is changed more than е. .m thirty times, this AGC system makes it possible to obtain on the grid of the powerful cascade the deviation of the high frequency voltage from the predetermined extremity by no more than 5%.

According to the conclusion the sentence is useful and can nkiiTH application .:

Subject invention

A device for automatically maintaining the transmitter output power level, comprising an automatic adjustment unit for the amplitude of excitation of the output stage, characterized in that, in order to improve the adjustment accuracy during telephone operation on a single sideband with an incompletely suppressed carrier, in comparison, the memory scheme is applied, used to memorize the level of the carrier frequency at the time of the absence of modulation until the next pause appears, and as a block for adjusting the amplitude of the excitation diodes included e in divider circuit coupled to the input of the modulator.