RU88231U1 - PHASE-COMPENSATION PRESELECTOR-MIXER OF RADIO RECEIVER - Google Patents

Abstract

Phase-compensation preselector-mixer of the radio receiver, consisting of a radio frequency amplifier (URC), a first and second mixer, a local oscillator, a 90 ° phase shifter, a phase inverter, an adder, a concentrated selection filter (FSS), the signal inputs of both mixers are interconnected and connected to the output of the URC the receiver, the output of the first mixer is connected directly to one input of the adder, and a phase inverter is connected to its second input; the local oscillator with its output is connected directly to the second input of the first mixer and to the second input of the second mixer through a 90 ° phase shifter; the adder output is connected to the FSS input, characterized in that an additional time differentiator and a signal level regulator are introduced into it, which are connected in series between the second mixer and the phase inverter.

Description

The utility model (PM) relates to the field of receiving radio signals.

Known phase compensation preselectors - mixers (frequency converters) of the radio signal receiver, described in the literature, for example, in:

1. Gorelov G.V., Fomin A.F., Volkov A.A., Kotov V.K.

The theory of signaling in rail transport - M :. Transport, 2001, p. 304-306.

2. Verzunov M.V. and etc. Single band modulation. - M .: Military Publishing House, 1962-p.95-101.

3. Momot EG Problems and technology of synchronous radio reception. - M .: Nauka, 1961 - p. 59-60.

By technical essence, the device closest to the utility model is described in the first source, which for this reason is taken as its prototype. The second and third sources describe analogues of PM.

The prototype consists of two mixers, a local oscillator, a 90 ° phase shifter, a 90 ° phase shifter, a phase inverter, an adder, a concentrated selection filter (FSS), and the inputs of both mixers are short-circuited and connected to the output of the radio frequency amplifier (URC) of the receiver; the output of the first mixer is connected directly to one input of the adder, and the output of the other mixer is connected to the second input of the adder through a 90 ° phase shifter and phase inverter connected in series; the adder output is connected to the FSS input; the local oscillator output is connected directly to the second input of the first mixer and to the second input of the second mixer through a 90 ° phase shifter.

The main disadvantage of the prototype is the relatively low degree of suppression of the mirror channel σ ₃ = 30 dB due to the large error Δφ = ± (2 ° -3 °) of the phase shift by an angle φ = 90 ° in the band phase shifter, which leads to a significant decrease in the quality of radio reception.

The technical result of the utility model is to improve the quality of radio reception by increasing the degree of suppression of the mirror channel to the required value of σ ₃ = 80 dB.

The essence of the utility model consists in the fact that the phase compensation preselector is a radio receiver mixer, consisting of a radio frequency amplifier (URC), first and second mixers, a local oscillator, a 90 ° phase shifter, a phase inverter, an adder, a concentrated selection filter (FSS), moreover, signal inputs both mixers are interconnected and connected to the output of the RF amplifier receiver, the output of the first mixer is connected directly to one input of the adder, and the phase inverter is connected to its second input; the local oscillator with its output is connected directly to the second input of the first mixer and to the second input of the second mixer through a 90 ° phase shifter; the adder output is connected to the FSS input, characterized in that an additional time differentiator and a signal level regulator are introduced into it, which are connected in series between the second mixer and the phase inverter.

The utility model is illustrated by drawings.

Figure 1 presents the structural diagram of the proposed phase compensation preselector - mixer, and figure 2 - the frequency of the useful signal ω _c , the local oscillator ω _g , the mirror channel ω _s , the intermediate frequency ω _etc.

Figure 1 shows:

1 - radio frequency amplifier (URC);

2,5 - mixers (signal frequency converters);

3 - local oscillators;

4 - phase shifters 90 °;

6 - time differentiator;

7 - adder;

8 - phase inverter;

9 - signal level regulator;

10 - filter concentrated selection (FSS);

11 - radio frequency amplifier (URC);

12 is a detector.

In general, this is a diagram of a radio receiver. The blocks of the phase compensation preselector - mixer are circled by a dashed line, and the introduced elements are circled by dots.

The operation of the circuit is as follows:

From the output of the RF amplifier 1, the sum signal the main u _c (t) = U _c sin [ω _c t + θ _c (λ _c, t)] and mirror u _s (t) = U _s sin [ω _s t + θ _s (λ _h , t)] channels, i.e. u ₁ (t) = u _c (t) + u _з (t), is fed to one of the inputs of the first 2 and second 5 mixers. Here θ (λ, t) is the phase component of the signal that carries information about the transmitted message λ (t). Oscillations of the local oscillator 3 u _g (t) = U _g sinω _g t is fed directly to the second input of the first mixer 2 and directly to the second input of the second mixer 5 through a phase shifter 4 at an angle of 90 °, at the output of which

u ₄ (t) = U _g sin (ω _g t + 90 °) = U _g cosω _g t = _g (t)

where ω _g > ω _{s is} selected, as shown in FIG. At the output of the mixers 2.5, which are equivalent to multipliers of signals with active load, oscillations are formed:

The high-frequency (including) components are not a difference, but the sum of the frequencies, which are then filtered out in the FSS.

Frequency difference in both cases equal to the intermediate frequency ω _ave = ω -ω _{r with s} = ω _r -ω

It can be seen that the vibrations u ₂ (t) and u ₅ (t) are squared together and therefore, despite the different signs of the signals of the main and mirror channels in u ₅ (t), exclude the mirror channel by subtracting u ₅ (t) from u ₂ (t) is not possible.

To exclude the indicated quadrature (phase shift of the signal by 90 °), the signal u ₅ (t) is differentiated by time in the introduced block 6, as a result of which there is an oscillation at its output:

As then the second term in parentheses can be neglected, i.e. the amplitude at cosines u ₆ (t) is constant, independent of the frequency Ω (t) = dθ / dt. The signs for the terms u ₆ (t) are the same as for u ₅ (t). In block 9, the amplitude of the signal u ₆ (t) is aligned with the amplitude of the signal u ₂ (t). The phase inverter 8 provides in the adder 7 the difference of the signals u ₂ (t) and u ₆ (t), i.e. u ₇ (t) = u ₂ (t) -u ₆ (t) = U _g U _c cos (ω _pr -θ _s (λ _s , t). It is seen that there is no mirror channel in u ₆ (t).

Next, the signal u ₇ (t) is fed to the input of the FSS 10, transmitting to its output only the main signal of the intermediate frequency ω _pr and not passing V.Ch. components.

So the phase-compensated method using the introduced elements suppresses the mirror channel. The degree of this suppression at the same signal levels u ₂ (t) and u ₆ (t) is determined by the expression: σ _3db = log sin0.5Δφ.

The introduced differentiator, made on the operational amplifier, provides a phase shift of 90 ° with an error of Δφ≤30 minutes and therefore σ _s ≥60 dB. Taking into account the input circuit of the receiver and the URF loop, σ _s = 80∂B> 35∂B.

The technical and economic effect of the utility model is to improve the quality of voice messages by suppressing the mirror and side channels of the reception by phase-compensating method with a high degree of 80 dB instead of 30 dB and simplifying and reducing the cost of the receiver.

Claims (1)

Phase-compensation preselector-mixer of the radio receiver, consisting of a radio frequency amplifier (URC), first and second mixers, a local oscillator, a 90 ° phase shifter, a phase inverter, an adder, a concentrated selection filter (FSS), the signal inputs of both mixers are interconnected and connected to the output of the URC the receiver, the output of the first mixer is connected directly to one input of the adder, and a phase inverter is connected to its second input; the local oscillator with its output is connected directly to the second input of the first mixer and to the second input of the second mixer through a 90 ° phase shifter; the adder output is connected to the FSS input, characterized in that an additional time differentiator and a signal level regulator are introduced into it, which are connected in series between the second mixer and the phase inverter.