DE3023861C2 - Pulse generator with adjustable pulse shape - Google Patents

Description

55

The invention relates to a pulse generator according to the preamble of claim 1. From DE-OS 15 37 077 a method for changing the hysteresis of electrical circuits is known. For forming impulses the signal path is split up and the correspondingly shaped and delayed signal parts are multiplicative mixed. From DE-PS 11 94 899 an arrangement for the digital generation of periodic wave trains is any given waveform known. A ring counter is sequentially activated by control pulses switched through. The output signals of the individual stages are generated by means of attenuators or amplifier stages each set to the desired amplitude and summarized.

Pulse generators are used for various purposes with adjustable pulse shape required. In particular to achieve monofrequency operation of Impatt oscillators, the controlling pulse must be individually tailored to the respective in terms of amplitude and pulse top shape Impatt diode can be adjusted.

The object of the invention is therefore to provide a pulse generator of the type mentioned in which the Pulse shape can be adjusted in a simple way, but very precisely in a wider range.

The invention is described in the claim.

The invention is explained in more detail below with reference to the figures. Fig. 1 shows a block diagram of the Pulse generator. Fig. 2 shows the comb generator of the pulse generator according to the invention in detail. Fig. 3 shows a pulse diagram; the pulse shapes are shown at the outputs of various components of the Pulse generator.

A square-wave generator Gen supplies a square-wave signal 1,1 'with the pulse width t _A and the duty cycle IaItß. About term elements Lzg, z. B. from Schottky-Schmitt triggers, the exact pulse width tp is set, 2 '. A ramp 3 'is generated from pulse 1 via a low-pass filter, the slope of which can be varied via a linear amplifier (video), 4'. The signals T and 4 'are fed to a mixer, e.g. B. a dual-gate FET, fed and multiplicatively linked together, S '. The pulse width, the pulse duty factor and the phase of the ramp are set simultaneously and firmly linked to one another via a central actuator, Stell. The base of the ramp 3 'or 4' must lie on the rising edge of the rectangular pulse 2 '.

The mixture of pulse top 4 'and basic pulse T at the FET ensures that the pulse width and rise or fall time specified once with 2' are adhered to and not influenced by the "pulse top circle".

With the circuit described so far, only linear pulse roofs can be generated. In many cases a piecewise linear or even a combination of exponential and linear roof shape is necessary. For this purpose, a comb generator (pulse circuit and comb) can be switched on as an alternative to the low-pass arrangement (ramp) which generates the ramp. The reason the pulse 1 is shortened tp to the width, 1. A delay line L with N intermediate taps, in Example 10 (or two delay lines each with 5 between concepts) provides N to each tp offset single pulses, in turn, t _P are long. The amplitude of each individual pulse can be set via a series resistor R _u , 3. After adding the individual pulses at the resistor R _m , a stepped total pulse of length t _ga = tp is available. Using a suitable amplifier, video, the pulse roof is smoothed, 4, and again mixed with the basic plus 2 'at the dual-gate FET.

The total plus 5 or 5 'after the mixer is then appropriately amplified (U, I).

The pulse generator according to the invention is particularly suitable as a power source for Impatt oscillators. He is individually adjustable to the respective Impatt diode, so that a single-frequency oscillator operation can be achieved is.

For this purpose 3 sheets of drawings

Claims (1)

Claim: Pulse generator with adjustable pulse shape, the signal path is split up and signal parts after Shaping and delay are mixed multiplicatively, especially for use as a power source for Impatt oscillators, characterized by the following features: 10 - A square wave generator (Gen) supplies a square wave signal (1, 1 ') with a pulse width t _A and a key ratio tAlt _B ; - The square-wave signal is fed to a (10) delay element (Lzg), at which the pulse width can be set to a desired value tp (2 '), and then to a first input of a multiplicative mixer (mixer); - The square-wave signal is fed to the other (1) a low-pass arrangement (ramp) in which it is converted into a ramp (3 '), - the ramp (3 ') is a linear amplifier (video) in which the slope of the same is variable (4 '), fed and then a second input of the multiplicative Mixer (mixer); - The output signal (5, 5 ') of the multiplicative mixer (mixer) is appropriately amplified (U, I) and fed to the load; - A central actuator (Stell) acts on the first on the square wave generator (Gen) to set the duty cycle, on the second on the delay element (Lzg) to set the pulse width tp, and on the third on the low-pass arrangement (ramp) to set the ramp phase; - A pulse shortener can be switched on in parallel and as an alternative to the low-pass arrangement (ramp) (Pulsver.) Switched with subsequent comb generator (comb); - The pulse shortener (Pulsverk.) Shortens the square wave signal (1) to a length t _P (2); - The comb generator (comb) consists of a delay line (Z,) with N intermediate terms, which emit N individual pulses of length t _P offset by for each, the amplitude of which is adjustable by means of a connected series resistor (R _u ); the individual pulses are added to a resistor (R _m ) so that the comb generator (comb) emits a step-shaped total pulse (3) of length t _ga = N · tp ä (p .