SU69052A1 - Push-pull amplifier high frequency - Google Patents

Description

High-frequency push-pull amplifiers are known in which complex and anodic oscillatory voltages are complex-shaped to increase the efficiency.

In the amplifier of the present invention, active resistors connected between the connection point of the cathodes of the lamps and the middle points of the grid input circuit and the anode of the oscillatory circuit serve to provide a complex form of oscillatory voltages in a wide range of amplified frequencies.

The circuit of the proposed amplifier is shown in FIG. 1, a | the form of oscillatory voltages in the grid and anode circuits of its lamps is shown in FIG. 2 and 3.

The oscillatory voltage (Fig. 2) supplied to the grids of the amplifier lamps contains in its composition the main Umgi and even (second Umgz and fourth (7mg4) harmonic components of the sinusoidal oscillatory voltage supplied from the previous cascade.

To obtain such a form, an additional ohmic resistance Kg is included in the grid circuit between the midpoint and the ground. At practically existing cut-off angles of the grid current Qg - 70-90 ° at the resistance Rg, voltage will drop due to the presence of the Second and Fourth harmonic components of the current in the grid pulse. Higher even harmonic components are not taken into account, since the pulse decomposition coefficients for these harmonic components are very small.

It is easy to show that the second harmonic component of the grid voltage in the half-period of the passage of current in the lamp when the co / O is in antiphase with the main oscillatory voltage Umgi cos co /. The oscillatory voltage of the fourth harmonic component in the component wif O is in phase with the voltage of the first harmonic component, since the decomposition coefficient for fig 7 (-90 has a negative value.

For 6g SO, the coefficients of the ratio of the vibrational stresses in the grid circuit with a large with sufficient accuracy are defined as

, V

gi 77 (,

- mg-2 gl

 IL iL

15.

 rngl "gt. The shape of the anode pulse is shown in FIG. 3. The cut-off angle of the anode current is chosen so that the coefficient of the "2 decompositions of the anode current pulse has a negative value. Calculations show that at cut-off angles О PO-115, the coefficient “2 has a negative value, and“ 4 - positive. By appropriate selection of Ug, Eg and Rg), it is possible to ensure that the ratio is in the range from 5 to 15. In the anode circuit of the amplifier, between the midpoint of the anode circuit and the ground, an additional polar resistance Roc By the optimal ratio of oscillatory voltages of the first and second harmonic components A – H, as is well known, for the case of the oscillation voltages of the first and second harmonic components acting in the anode circuit, the optimum coefficient of using the anodic voltage Neither the first garliunical component will have a Bingo at Kg - 2.5-3. An increase in the utilization rate for DL / Cz 21/2 is obtained by ½ times, i.e. - | / 2; -Crit. In this case, the resistance of the remaining higher even harmonic components of the anode current will also fall on the resistance. To a small extent, the fourth harmonic component influences the shape of the anode oscillatory pitch, while all other even higher harmonic components are practically not due to a low pulse decomposition coefficient. The action of the oscillating voltage of the fourth harmonic component is beneficial and gives an opportunity to even more magnify the coefficient of anodic voltage use by the first harmonic component. For example, with y, and 4rit. 0.9 the coefficient of efficiency of the generator on the first harmonic component is equal to: P 5 V - - O 5 V. F 5 / -, - / I -, - / I i, Э eккр. - oE / o. Thus, in the proposed amplifier, it is quite possible to increase the power by more than two times. The advantage of this circuit is that the additional equivalent impedances in the anode and grid circuits are ohmic, which is important when using this method on band transmitters. On short-wave transmitters, salt-resistances can be used, and this will have a significant reduction in non-linear distortion during modulation. The subject of the invention A push-pull high-frequency amplifier in which a complex shape is given to increase the efficiency of the grid and anode oscillatory voltages, characterized in that to provide a complex shape of the oscillatory voltages in a wide range of amplified frequencies, active resistances are applied between the point of connection of the cathodes of the lamps and the mean of the points of the grid input circuit and the anode oscillatory circuit.

FIG. 2

FIG. one

FIG.

 U /

 . i4 D

 Llr-.

I2C11

 / V bi. ™ Y

  : U (-:

- -tz; 1