SU468177A1 - Pulse average frequency meter - Google Patents

Description

(54) MEASURING MEDIUM FREQUENCY PULSES metering 2 and integrating 3 capacitors, diodes 4 and 5 and the discharge resistor 6, the parameters of the capacitors and resistors in different integrators can be different, and the output amplifier, including the first stage with the common base on the transistor 7 a collector load of soy from resistor 8 and diodes 9 and 1b, and an emitter follower on transistor 11 with resistor 12. A forming device (electronic switch) switches one output capacitor 2 between the pulses to its input do the poles of the power source. As a result, capacitor 2 is charged through diode 4 from the power supply, then discharged to capacitor 3 through diode 5. Diodes 4 and 5 are flattened so that a positive potential is created at the signal output of capacitor 3, and the discharge of this capacitor through resistor 6 creates an input current amplifier. The collector current of the transistor 7 creates on the load, consisting of a resistor 8 and a diode 9, a positive polarity voltage, ko-25 and

The second is transmitted by the output of the IFN transistor 11. The amplifier operates without an initial bias current, so it does not consume current B without a signal and for its power supply a voltage source slightly higher than the desired maximum output voltage, e.g. 0.3-1 V, is needed. This is important when transmitting the output voltage over the tem-tric channels, since there is no need for protective overload devices, complicating. circuitry and impair measurement accuracy. To ensure a linear relationship between the input current and output voltage, diode 9 is installed, the diode and transistor 11 are taken from the same type of material, and resistors 8 and 12 are of approximately the same resistance value for equal diode and emitter currents. In addition, the diode 9 compensates for temperature variations in the voltage at the emitter base junction of transistor 11, by raising the temperature; new stability The diode 10 performs temperature compensation for the reverse currents of the collectors of the transistors 7 and 11, as well as temperature changes of the currents of the diode, integrators. With an increase in temperature, the return currents of the collectors grow, and the currents of the integral. If reverse polarity is needed, it is necessary to reverse it: the polarization of all the diodes, the polarities of the transistors and the polarization of the power source.

Subject invention

Measuring the average frequency of pulses, containing a forming device, diode integrators with metering capacitors, pp transistor, pp p transistor. Rarators usually fall, which creates partial compensation. Diode 10 is taken with such a reverse current, at elevated temperature, to best compensate for these changes. If the thermistor 7 is taken germanium with a small reverse collector current, and transistor 11 is silicon, then diode 10 can be excluded from the circuit. The output stage according to the common base circuit has the lowest input impedance, which creates the best for building a logarithmic IF, with the summation of the currents of diode integrators. In addition, such a circuit has good temperature stability due to gain due to a slight change in the coefficient of direct current transfer with temperature. The circuit has normal T polarization: in the absence of a signal, the output voltage is zero, and when the input pulses are output, a potential positive to the common bus is created. This normal polarization is achieved without introducing an additional power source to zeroing intermediate sweating — a power source, resistors and diodes, which are distinguished by the fact that, in order to simplify the circuit and increase temperature stability, the diode integrators through the resistor are connected np transistor included in the scheme with a common base, the collector of which is connected to the base nnp transistor included in the scheme with a common collector, and the base of this transistor is connected to the forming device s parallel; a circuit consisting of a diode connected in the forward direction with a resistor, and a diode connected in the opposite direction.

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