Controlled selective amplifier

FIELD: radio engineering, communication.

SUBSTANCE: invention relates to radio engineering, and specifically to controlled selective amplifiers. The selective amplifier comprises a signal source connected to the base of a first input transistor, a second input transistor, a first current-stabilising two-terminal element connected between the emitter of the first input transistor and a first power supply bus, a second current-stabilising two-terminal element connected between the emitter of the second input transistor and the first power supply bus, a first balancing capacitor connected between the emitter of the first and second input transistors, a first frequency-setting resistor connected between the collector of the first input transistor and a second power supply bus, a second balancing capacitor and a second frequency-setting resistor. The second balancing capacitor is connected between the base of the second input transistor and the collector of the first input transistor; the second frequency-setting resistor is connected between the base of the second input transistor, which is connected to the output of the device and a common power supply bus, wherein the frequency-setting resistor is connected in parallel via alternating current to an additional balancing capacitor.

EFFECT: high Q-factor of the amplitude-frequency characteristic and voltage gain at quasi-resonance frequency.

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The invention relates to the field of radio engineering and communication and can be used in the filtration devices of the radio communication systems, radar, etc.

In the tasks of separating high-frequency signals are now widely used integrated operational amplifiers with special items RC-correction form of the amplitude-frequency characteristic of the resonance type [1, 2]. However, the classical construction of such election amplifiers (in-amps) is accompanied by significant energy losses, which go primarily to ensure the static mode, a sufficiently large number of secondary transistors constituting the operational amplifier [1, 2]. In this regard, a very urgent task of building a specialized selective amplifiers, bipolar transistors, providing a selection of narrow-spectrum signal with a sufficiently high quality factor (Q) of the resonance characteristics (Q=2÷10) without the "extra" active elements with low power consumption.

Known schemes Yiwu based on bipolar transistors, which provide the formation of the amplitude-frequency characteristics of the gain of the voltage in a given range of frequencies Δf=f_in-f_n[3-28]. Moreover, the upper cutoff frequency f_insometimes is formed by the inertia of the transistors of the circuit capacitance to the substrate), and the bottom f_ndetermined corrective capacitor.

The closest prototype of the proposed device is the selective amplifier presented in the patent US 4.267.518 fig.6. It contains the signal source 1 is connected to the base of the first 2 input transistor, the second 3 input transistor, the first 4 dakotabilities dvukhpolosnykh connected between the emitter of the first 2 of the input transistor and the first 5 bus power source, the second 6 dakotabilities dvukhpolosnykh connected between the emitter of the second 3 of the input transistor and the first 5 bus power supply, the first 7 adjustment capacitor connected between the emitter of the first 2 and second 3 input transistors, the first 8 frequency control resistor connected between the collector of the first 2 of the input transistor and the second 9-bus power supply, 10 second correction capacitor, the second frequency control 11 resistor, and the collector of the second 3 input transistor connected to the constant current from the second 9-bus power source.

A significant disadvantage of the known PS-prototype is that it does not provide high quality

$$Q\approx \frac{f_0}{f_{\mathrm{in}}-f_n}$$

amplitude frequent is based characteristics (AFC) and high gain voltage To ₀>1 at the frequency of quasiresonance (f₀).

The main objective of the present invention is to increase the quality factor of the frequency response Yiwu and its conversion gain voltage (₀on the frequency of quasiresonance f₀. This allows in some cases to reduce the total energy consumption and implement high-quality polling device with Q=5÷50.

The problem is solved in that in the election amplifier figure 1 source 1 connected to the base of the first 2 input transistor, the second 3 input transistor, the first 4 dakotabilities dvukhpolosnykh connected between the emitter of the first 2 of the input transistor and the first 5 bus power source, the second 6 dakotabilities dvukhpolosnykh connected between the emitter of the second 3 of the input transistor and the first 5 bus power supply, the first 7 adjustment capacitor connected between the emitter of the first 2 and second 3 input transistors, the first 8 frequency control resistor connected between the collector of the first 2 of the input transistor and the second 9-bus power supply, the second 10 correction capacitor, the second 11 frequency control resistor, and the collector of the second 3 input transistor connected to the constant current from the second 9-bus power supply, there are new elements and communications-10 second correction capacitor included m the forward base 3 second input transistor and the collector of the first 2 input transistor, the second 11 frequency control resistor connected between the base of the second 3 input transistor associated with the output device 13, and a common bus 12 power sources, and parallel to the second 11 castorocauda resistor included AC additional corrective capacitor 14.

The amplifier circuit of the prototype is shown in figure 1. Figure 2 presents the diagram of the inventive device in accordance with the invention.

Figure 3 presents the scheme PS 2 n-p-n SiGe transistors in the Cadence environment.

Figure 4 shows a logarithmic amplitude-frequency (LACH) and phase (PFC) features PS 3 in the frequency range from 1 MHz to 100 GHz with Cvar=50pF, R12=128 Ohm, C1=280 FF.

Figure 5 shows LATCH and PFC PS 3 in the frequency range from 1 MHz to 100 GHz with Cvar=5pf, R12=131 Ohms, C1=450 FF.

Figure 6 shows LACK PS 3 in the frequency range from 1 MHz to 100 GHz with Cvar=5 pF and 50 pF.

7 shows LACK PS 3 in the frequency range from 1 MHz to 100 GHz with Cvar=50pF and current Ivar, changing in the range from 0.4 mA to 1 mA with a step of 0.2 mA.

On Fig presents LATCH PS 3 in the frequency range from 1 MHz to 100 GHz with Cvar=5pF and current Ivar, changing in the range from 0.4 mA to 1 mA with a step of 0.2 mA.

Selective amplifier figure 2 contains the signal source 1 is connected to the base of the first 2 input transistor, the second 3 input transistor, the first 4 tokota the lyse dvukhpolosnykh, connected between the emitter of the first 2 of the input transistor and the first 5 bus power source, the second 6 dakotabilities dvukhpolosnykh connected between the emitter of the second 3 of the input transistor and the first 5 bus power supply, the first 7 adjustment capacitor connected between the emitter of the first 2 and second 3 input transistors, the first 8 frequency control resistor connected between the collector of the first 2 of the input transistor and the second 9-bus power supply, 10 second correction capacitor, the second 11 frequency control resistor, and the collector of the second 3 input transistor connected to the constant current from the second 9-bus power source. The second 10 correction capacitor connected between the base of the second 3 of the input transistor and the collector of the first 2 input transistor, the second 11 frequency control resistor connected between the base of the second 3 input transistor associated with the output device 13, and a common bus 12 power sources, and parallel to the second 11 castorocauda resistor included AC additional corrective capacitor 14.

Consider the circuit of figure 2.

The input signal source 1 (u_I) changes the collector current of the first input transistor 2. Into force of the comprehensive nature of its collector load circuit at the output 13 Yiwu plays Ampl tudno-frequency characteristic of the band-pass type the capacitor 10 provides a high suppression of the input signal in the lower frequency (f<f₀), and the capacitor 14 in the upper frequencies (f>f₀). Function large-scale transformations collector current of the transistor 2 is implemented on the resistors 8 and 11.

The complex transmission coefficient PS 2 as the ratio of the output voltage (output 13) to the input voltage u_I(1) is determined by a formula, which can be obtained by using methods of analysis of electronic circuits

$$K\left(jf\right)=\frac{u_{13}}{u_{\mathrm{in}x}}=K_0\frac{jf\frac{f_0}{Q}}{f_0^2-f^2+jf\frac{f_0}{Q}},\left(1\right)$$

where f is the frequency of the input signal;

f₀frequency quasiresonance electoral amp;

Q - q AFC electoral amp;

To₀the gain of the DUT at a frequency of quasiresonance f₀.

If the frequency of quasiresonance f₀reacti is the great resistance of the capacitor 7 is much less than the sum of the emitter resistances of the transistors 2 and 3, then

$$f_0=\frac{1}{2\pi \sqrt{C_{10}{C}_{14}{R}_8{R}_{11}}},\left(2\right)$$

where C₁₀With₁₄, R₈, R₁₁- parameters of the elements 10, 14, 8, and 11.

Thus q Yiwu is determined by the formula

$$Q^{-1}=D_0+\sqrt{\frac{C_{10}}{C_{14}}}\sqrt{\frac{R_8}{R_{11}}}\left(1-\frac{{\alpha }_2{R}_{11}}{h_{11.3}+h_{11.2}}\right),\left(3\right)$$

where α₂- gain current of the emitter of the transistor 2;

h_11.i- h-parameter of the i-th transistor in the circuit with a common base;

D0=(C10C14+C14C10)R11R8

- equivalent attenuation passive frequency driver

dependent circuit in the collector of the transistor 2.

By choosing the parameters of the elements included in the formula (3), we can ensure that Q>>1.

If you implement the condition

$$\frac{{\alpha }_2\sqrt{R_8{R}_{11}}}{h_{11.2}+h_{11.3}},\left(4\right)$$

the quality factor Q and the gain K₀

$$Q=\sqrt{\frac{R_8}{R_{11}}}\cdot {\left[\sqrt{\frac{C_{10}}{C_{14}}}+\sqrt{\frac{C_{14}}{C_{10}}}\right]}^{-1},\left(5\right)$$

$$K_0=Q\sqrt{\frac{C_{10}}{C_{14}}}.\left(6\right)$$

However, in the General case the formula for the gain K₀in the complex transmission coefficient (1) is

$$K_0=-Q\frac{{\alpha }_2}{h_{11.3}+h_{11.2}}\sqrt{R_8{R}_{11}\sqrt{\frac{C_{10}}{C_{14}}}}.\left(7\right)$$

An important feature is the ability to optimize its parametric sensitivity. The optimal ratio asesoramiento capacitors 10 and 14 (C ₁₀=C₁₄=C). In this regard, the desired value of the quality factor Q can be implemented parametrically - establishing a certain ratio between the resistances of the resistors 11 (R₁₁and h_11.2h_11.3that are determined by the currents of the current sources 4 and 6.

$$h_{11.2}=h_{11.3}\approx {\phi }_T/I_0,\left(8\right)$$

where φ_T≈25 mV - temperature capacity;

I₀- some reference value of the current, for example, I₀=1 mA.

Therefore, the parametric condition for the realization of the required quality can be easily achieved by selecting the modes of operation of the transistors 3 and 2. In particular, when performing equality

$$\frac{2{\phi }_T}{{\alpha }_2{I}_0}=R_{11},\left(9\right)$$

provides extremely low sensitivity figure of merit Yiwu to a capacitive circuit elements. Indeed, the above optimality ratio of their nominal price is s (C ₁₀=C₁₄enables equality

$$S_{C_{10}}^{K_0}=-S_{C_{14}}^{K_0}=\frac{1}{2},S_{C_{10}}^Q=S_{C_{14}}^Q=0.S_{R_8}^Q=S_{R_8}^{K_0}=S_{R_{11}}^Q=-S_{R_{11}}^{K_0}=\frac{1}{2}\left(10\right)$$

In practical problems, the condition (10) can be used to improve the stability of the parameters in Yiwu tuning mode or scale of frequency tuning quasiresonance, which is feasible to implement the current I₆=I_var.

The equality C₁₄=C₁₀=C does not contradict the condition of ragnorokonline passive circuit elements (R₁₁=R₈=R). In this case, the parameter R

$R=\frac{2{\phi }_{T}3-1/Q}{I_0{\alpha }_2},\left(11\right)$

ensuring implementation of the required quality Yiwu.

Presents drawings 4-8 the simulation results of the proposed PS 2-3 confirm these properties of the proposed schemes.

From Fig.6, it follows that the capacitance of the capacitor 7 (C₇=C_var) has a positive effect on the attenuation of the input signal in the low frequency range. In addition, by changing the static current of the transistor 3 can be controlled by the parameters of the electoral amplifier - q and gain (see Fig.7, Fig).

BIBLIOGRAPHIC LIST

1. Design of Bipolar Differential OpAmps with Unity Gain Bandwidth up to 23 GHz / N.Prokopenko, A.Budyakov, K.Schmalz, C.Scheytt, P.Ostrovskyy // Proceeding of the 4-th European Conference on Circuits and Systems for Communications - ECCSC'08. / - Politehnica University, Bucharest, Romania: July 10-11, 2008. - pp.50-53.

2. SHF SF-blocks of communication systems on the basis of the fully differential operational amplifiers / Prokopenko N. N., Budakov A.S., .Schmalz, .Scheytt // problems of development of perspective micro - and nanoelectronic systems - 2010. The conference proceedings. / Under the General editorship of academician Alemannische. -M.: IPPM RAS, 2010. - S-586.

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Selective amplifier containing a signal source (1)connected to the base of the first (2) of the input transistor, the second (3) input transistor, the first (4) dakotabilities dvukhpolosnykh connected between the emitter of the first (2) of the input transistor and the first (5) bus power supply, the second (6) dakotabilities dvukhpolosnykh connected between the emitter of the second (3) input transistor and the first (5) bus power supply, the first (7) adjustment capacitor connected between the emitter of the first (2) and second (3) input transistors, the first (8) frequency control resistor connected between the collector of the first (2) input implemented the Torah and second (9) bus power supply, the second (10) correction capacitor, the second (11) frequency control resistor, and the collector of the second (3) input transistor connected to the constant current from the second (9) bus power source, characterized in that the second (10) correction capacitor connected between the base of the second (3) input transistor and the collector of the first (2) of the input transistor, the second (11) frequency control resistor connected between the base of the second (3) input transistor associated with the output device (13), and a common bus (12) power sources, while the second (11) castorocauda resistor included AC additional correction capacitor (14).