DE1815752A1 - Circuit arrangement for generating low-frequency images of high-frequency signals to be examined - Google Patents

Description

IV - 306

12. 12. 1968 Cr / KL

ELTRO GMBH & CO., GESELLSCHAi ¹ O? FOR RADIATION TECHNOLOGY Heidelberg, Schloßwolfsbrunnenweg 33

Circuit arrangement for generating low-frequency images of high-frequency signals to be examined

The invention relates to a circuit arrangement for generating electricity low-frequency images of 'high-frequency signals to be examined.

Such circuit arrangements are often also as Signal sampling circuits or sampling circuits and are already known, especially in oscillograph technology for displaying the shortest possible time Operations.

The known circuits usually have two series-connected, biased in the retirement in the reverse direction Diodes or four diodes coupled together in a bridge circuit. If the bridge circuit is adjusted correctly is thereby prevented that the momentary open-triggering the diodes get into the device under test and consequently produce undesirable echo pulses.

In addition, the known circuit arrangements are provided with relatively complicated negative feedback networks, which have the task of achieving the most exact, error-free display of impulses.

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ORIGINAL INSPECTED

In some applications it has now been found that the "with the" known circuit arrangements The effort expended is far too high and is practically not worth it, especially not if it is done in advance no input voltages that are too high need to be processed or if it is of no importance that the sum open the receiving diodes serving T as timpuls under Circumstances at the same time enters the test object.

The invention is therefore based on the object as a Sampling circuit to create a suitable circuit arrangement, for the implementation of which only a few components are required.

According to the invention, this object is achieved by only one single, periodically and briefly controllable receiving diode containing scanning signal circuit solved.

If a periodically recurring pulse of extremely short acidity is to be made visible, it becomes visible in the case of the invention Circuit arrangement given to the blocked receiving diode by a second, also periodically Occurring pulse, which is either phase-modulated or a slightly different one compared to the RF pulse to be imaged Has pulse repetition rate, is opened. Due to the phase modulation or the different pulse repetition frequency of the tactile impulse this hits with each new period with another instantaneous value of the impulse to be imaged together. At the output of the receiving diode there are thus pulses whose amplitudes are a function of the amplitudes of the key pulse and the corresponding instantaneous value of the impulse to be mapped. As a result, the Sampling pulses are amplitude-modulated. The modulation voltage then obtained by simple integration is set represents a low-frequency image of the high-frequency pulse to be examined.

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According to a development of the invention Circuit arrangement is provided with the receiving diode connected in series charging capacitor as integrator serves and at the same time the peak rectification the blocking voltage for the receiving diode formed by the scanning pulses that open the receiving diode supplies. This measure provides an additional voltage source to generate the reverse voltage for the Receiving diode made dispensable, since the charging capacitor is anyway to store the tactile pulses and the received HP signal is required.

The invention is further explained with reference to FIG attached drawings. In the context of exemplary embodiments:

1 shows a circuit arrangement according to the invention (block diagram) and

ig. 2 associated pulse diagrams.

In the block diagram according to FIG. 1, a device under test is denoted by 1 and an RF pulse generator by 2. This one will applied by a control generator 4 with a control voltage, due to which in the generator 2 using a switching diode high-frequency pulses are formed, - which then reach the test object 1.

At the same time, the control voltage generated by the control generator 4 runs into a phase modulator stage 5 and is here converted to a sawtooth voltage of the same frequency. The phase modulator stage 5 will continue acted upon by a sawtooth generator 11 with a low frequency sawtooth voltage. Both tensions

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are processed in the phase modulator stage 5 in such a way that a square pulse train with the frequency of the control voltage of the control generator 4 is produced at its output ο This square pulse train is length-modulated by the low-frequency sawtooth voltage of the sawtooth generator 11 and serves as the control voltage for the tactile pulse generated at or 6. This contains a switching diode, e.g. a tunnel diode or a step recovery diode, which is caused to switch by the control voltage supplied to the pulse generator 6, so that a corresponding square-wave voltage is generated at its terminals, the "switching edges of which form the pulse pulses" after differentiation (cf. Fig. 2b).

; The sampling signal circuit 3, which is the actual sampling circuit represents, now furthermore contains only one receiving diode 7 »which is caused by the pulse pulses of the generator is opened briefly »In the idle state, the receiving diode 7 is blocked, by means of a the receiving diode 7 series-connected charging capacitor by peak rectification of the receiving diode 7 blocking voltage formed by opening key pulses is supplied, which is in the form of a direct voltage and one of these superimposed, through periodic storage and re-use the pulse voltage at the charging capacitor 8, sawtooth-shaped alternating voltage occurs (see. Fig. 2c).

If the high-frequency measuring pulse coming from the test object 1 (see »Fig. 2a) reaches the receiving diode 7 at the moment if this is opened by a key pulse, this creates a voltage at the charging capacitor 8, the amplitude of which depends on the amplitude of the probe pulse and the instantaneous amplitude of the receiving RF pulse, as a result the phase modulation of the probe pulses (see. Fig. 2b) this

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coincide with a different instantaneous value of the RF pulse to be mapped for each new period (see. Fig. 2a / b).

The voltage at the charging capacitor 8 therefore experiences slow changes in its maximum amplitude (see FIG. 2d). this corresponds practically to an amplitude modulation of the probe pulses. At the input of the charging capacitor 8 in parallel switched LF amplifier 9 is finally obtained a low-frequency image of the received RF pulse, which equal to the modulation voltage F ™ according to FIG. 2d is. A signal output is denoted by 10.

The circuit arrangement according to the invention is distinguished above all by the fact that it has a very simple structure is. It can always be used with advantage in those cases in which the requirements for accuracy the momentum display are not too high and therefore complicated measuring arrangements would not pay off.

In addition, the use of only a single receiving diode in the scanning signal circuit brings further benefits The advantage is that the receiving system is very low-reflection is constructed.

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Claims (2)

IV - 306 12/12/1968 Cr / Pl Claims 1 · Circuit arrangement for generating low-frequency Images of high-frequency signals to be examined, characterized by only one, periodically and briefly controllable receiving diode (7) containing scanning signal circuit (3) 2. Circuit arrangement according to claim 1, characterized by one connected in series with the receiving diode (7) Charging capacitor (B) »which serves as an integrator and at the same time that through peak rectification the reverse voltage generated for the receiving diode (7) supplies. 009826/1215 INSPECTED