SU1226317A1 - Stroboscopic mixer - Google Patents

Abstract

The invention relates to a radio measuring technique and can be used in strobe converters and oscilloscope oscilloscopes. The purpose of the invention is to expand the functionality. The device contains resistors 1, 3 and 4, a field-effect transistor 2, mixing diodes 5-8, a storage capacitor 9, a buffer unit 10, a decoupling unit 11, and ballast resistors 12 and 13. The device measures the absolute levels of the input signals by reducing the emission strobe pulses to the device input, expand the values of the output impedances of signal sources that the device can operate by introducing a field effect transistor, increase the linearity of the conversion by stabilizing the operating point of the bridge mixer and simplify device adjustment by decoupling the diode bridge and entering the device. 1 il. t / C Circuit reverse / h Strobinptslsy

Description

The device relates to a radio measuring technique and can be used to solve a wide range of measurement tasks in strobe converters, strobe links: logographs.

The aim of the invention is to expand the functionality of the ability to measure the absolute levels of input signals by reducing the emission of strobe pulses to the input of the device to expand the output resistance values of signal sources that the device can operate by introducing a field-effect transistor. , stabilizing the working point of the bridge mixer and simplifying device adjustment at the expense of separation of the diode bridge and device input a.

The drawing shows a diagram of the device.

The device contains an input resistor 1, a field-effect transistor 2, resistors 3 and 4, a mixing diode 5-8j storage capacitor 9, a buffer unit 10, an output unit 11, balanced resistors 12 and 13, while the gate of transistor 2 is the device input and connected to the input resistor 1, the other end of which is connected to the common bus NOY5, the drain of the transistor 2 is connected: through a resistor 3 to the cathodes of diodes 5 and 6s, the first output of the decoupling unit 11 and the balanced resistor 125 to the other end of which , the anode of the diode 6, the first entrance to the buffer The unit 10, one plate of the storage capacitor 9, the other facing of which is connected to the common bus, and the balancing resistor 13, the other end of which is connected to the anodes of the diodes 7 and 8, the second output of the decoupling unit 11 and through the resistor 4 and with the anode of diode 5 and cathode of diode 7, the second input of the buffer unit 10 is the input of the supply voltage, and the output is the output of the device, the second input of the decoupling unit 11 is the input of the negative bias voltage and stShH , positive, first input of decoupler 11 - input

positive bias voltage and negative-gate strobe pulses, in addition, the inputs of isolation unit 11 are feedback voltage inputs.

The device works as follows.

In the initial state, the mixing diodes 5-8 are closed by a bias voltage ± E, which is fed through the coupling unit 11 to the terminals of the cathodes of the diodes 5 and 6 and the anodes of the diodes 7 and 8, under the effect of strobing VLMnynbCOB, coming in the same circuits as and t Е, the diodes 5-8 ot1-: break down for a short period of time and the input signal passing through the transistor 2 gates. The capacitor 9 is quickly charged, and when the strobe-action signal is discharged through large input resistance of the buffer block 10 and reverse resistance diodes. Thus, an extended pulse 5 is generated, the amplitude of which carries information about the signal at the time of gating. The extended pulse through block 10 is fed to the output of the device. Block 10 has a very large input resistance (Sony Mohm),

Unit 11 (in the form of a decoupling and balun transformer) ensures safe isolation of the capacitance diodes from the strobe pulses generator and bias circuits, and also balances the strobe pulse

The feedback voltage (through the bias circuit) is fed to the input of block 11 and further to diodes 5-8: catches 5 and 6, circuit 7 and 8, through resistors 12 and 13 to the cathode of diode 8 and to the anode of diode 6 , and through resistors 3 and 4, the voltage applies respectively to the drain and source of transistor 2 and to the output of the anode of diode 5 — the cathode of diode 7, i.e. through the transistor 2, the feedback voltage is fed to the common output of the cathode of diode 7 and the anode of diode 5: all four common outputs of the diode bridge are covered by feedback, which is significant. Through resistors 12 and 13, the feedback voltage is supplied to the capacitor 9 and the input of the block 10. The feedback feedback ensures the high linearity of the converter, in which the device operates, since the B circuit does not process the entire input signal, but only the increment.

Transistor 2 transmits to the source (and to the common output of the cathode of diode 7 and anode of diode 5) all changes in the voltages applied to its drain and source through resistors 3 and 4. Transistor 2 has a large input resistance (hundreds of MΩ); the resistance of the resistor 1 is 100 kΩ (without deterioration of the device parameters).

Resistors 3, 4, 12, and 13 have a rather large resistance (100 kΩ) and weakly shunt-mixing diodes. If we do without resistors 12 and 13 and rely on the large reverse resistance of the diodes of the bridge, this will lead to the following. To ensure this, an additional wire will be required to connect the feedback voltage to the common output of diode 6 and cathode of diode 8, to capacitor 9 and to the input of unit 10, and an additional resistor, which is simply unacceptable under the conditions of the probe (additional noise appears, the thickness of the probe cable increases and its flexibility decreases, the dimensions of the probe itself increase). In addition, the resistance value of the additional resistor will be 2-3 kΩ to provide the required division factor in the feedback circuit and the additional resistor will determine the constant discharge of the capacitor 9 rather than the reverse resistance of the bridge diodes, i.e. There is no superior. Thus, the use of resistors 12 and 13 and block 10 is logical, justified and technically true, which confirms the simple

payment.

Block 10 is a buffer cascade between the output of the device and the output of the diode bridge, the main purpose of which is to provide a high input resistance, and consequently, a longer discharge time constant of the storage capacitor to provide the required duration of the expanded pulse, and transmit the expanded pulse to the output of the device. Unit 10 may be, for example, a cascade on a transistor, as in a known device.

2263174

Transistor 2 is a cascade between the input of the device and the input of the diode bridge (the cathode of diode 7 is the anode of diode 5). Its purpose is to transfer all voltage variations to its inputs through its resistors 3 and 4 to its 5 output, and to ensure reliable isolation (at high input resistance) of the device and diode bridge inputs. At the same time, during the gating period, strobe pulses across resistors 3 and 4 do not arrive at the input of the diode bridge or at the source of transistor 2, since the values of re-5 of resistors 3 and 4 are chosen as such

so that the strobe pulses are attenuated during the gating time on resistors 3 and 4 (in this case, this is achieved by the fact that

20 resistors are on the order of

100 kΩ). Typically, the bandwidth is 1-1.5 GHz and the use of a field-effect transistor with its own bandwidth

25 12-18 GHz (commercially available) and will not change the bandwidth of the mixer and will not impair its characteristics.

thirty

Claims (1)

Invention Formula A stroboscopic mixer containing an input resistor connected between the device input and a common bus, four mixing diodes in which the cathodes of the first and second diodes and the anodes of the third and fourth diodes are connected in pairs, the anode of the first diode is connected to the cathode of the third diode, the anode of the second diode connected to the cathode of the fourth diode, one obkoy oh storage capacitor, the first input of the buffer unit and the first and second balanced. resistors, the common output cathode of the first and second digdov connected with the first output of the decoupling unit, the general output of the ayuds of the third and fourth diodes is connected to the second output of the decoupling unit, the first the input of which is the input of the positive bias voltage and the strobe pulses of the polarity, and the second input is the input of the negative bias voltage and strobe pulses of positive polarity, the inputs of the isolation unit being the inputs of feedback voltage, the other lining of the accumulator condator, is connected to the common bus 5, the second ejection of the buffer unit is connected to the input of the power supply, and the output with the output of the device, about t of l n h and y-- y and with the fact that; in order to expand the functionality of the linearity and simplify the adjustment process., in Hei. o input two resistors and a field effect transistor, the gate of which is connected to the gate device ,, drain through the first resistor is connected to the common output of the cathodes of the first and second diodes., the source  The qepesi second resistor is connected to both the output of the anodes of the third and four Berth diodes and the cathode of the third diode; the second terminals of the first to the second balanced resistors connected to the first and second outputs of the decoupling unit respectively