RU2101856C1 - Device for doubling of pulse repetition frequency - Google Patents

Abstract

FIELD: radio engineering; radio communication. SUBSTANCE: device has first 1 and second 2 NOT gates, first 3 and second 4 AND gates, univibrator 5 and OR gate 6. In such circuit doubling of input pulse sequence is effected only by sequential execution of logical operations (multiplication, addition and negation) which makes it possible to do without maintaining the controllable characteristics of device on required level and without feedback circuit as a whole. EFFECT: higher stability. 3 wdg

Description

 The invention relates to radio engineering, and in particular to measuring equipment, and in particular can be used in radio communication technology, for example, in frequency synthesizers of transceiver installations with software tuning of the operating frequency (PFRCH) as a pulse frequency multiplier.

 A known pulse repetition rate multiplier comprising a pulse shaper, a delay element, a reversible counter, a digital adder, a memory register, a digital-to-analog converter, and a controlled generator (ed. St. N 1298831, 1987).

 However, in the specified multiplier to obtain the output pulse repetition rate, you must first set the binary code and the value of the reference voltage. This reduces the speed of the device with fast changing data to form the output pulse repetition frequencies.

 A well-known periodic pulse repetition frequency multiplier comprising a clock pulse generator, an element And, a trigger, a pulse frequency divider, an element NOT, a trigger with corresponding functional relationships (ed. St. N 1298878, 1988).

 The specified multiplier, providing a fairly stable pulse repetition rate, does not allow the formation of a rapidly changing frequency grid when they are connected in frequency synthesizers by the cascade method.

 The closest technical solution to the proposed one is a device that contains a sawtooth voltage generator (GPI), two single vibrators, a phase detector (PD), an OR element (ed. St. N 1352626, 1988). The input of the device is connected to the input of the GUI, the first one-shot and the second input of the OR element. The input of the GUI is connected to the second input of the PD. The input of the first one-shot to the input of the second one-shot, the output of which is connected to the first input of the PD and the first input of the OR element. The output of the PD is connected to the controlled input of the first one-shot. The output of the device is the output of the OR element.

 However, the prototype device has the following disadvantages: low stability of the double pulse repetition rate, which is determined by the linearity of the working section of the sawtooth voltage and characterized by a non-linearity coefficient γ [see L. M. Golgenberg "Pulse and digital devices." M. Communication] It is known that the “saw” in the GUI has an exponential growth law. To obtain the required g values, it is necessary that the supply voltage is g times higher than the initial one. Therefore, to achieve linearity, as a rule, only 10 initial sections of the “saw” (close to linear) are used. However, to achieve the required level of growth of the "saw" it is necessary to increase the supply voltage by 10 times. Given that the pulse width in the prototype is relatively low, the implementation of such a condition in digital devices encounters significant difficulties associated with achieving linearity and, therefore, the required stability of multiplication.

 In addition, the time interval necessary for the formation of a given frequency doubling is determined by the time of establishment of the stationary process in the feedback circuit and in the prototype it is a relatively large time period. And this leads to a delay in the operation of the device after the arrival of the first input pulse. This drawback does not allow the use of a prototype device in a cascade connection to obtain a frequency grid in frequency synthesizers in transceiver installations with frequency hopping, because IFRP provides for rapid frequency changes when forming a frequency grid. With the indicated delays, this will lead to an “onset” of instability when switching from one operating frequency to another and, ultimately, to disrupt the operation of the frequency synthesizer, controlled by signals from the frequency hopper.

 The presence in the prototype feedback circuit "FD-one-shot-GPN" requires a control voltage that controls the duration of the pulse generated by the first one-shot. When the transition time of the “saw” through the zero level coincides with the pulse generated by the second one-shot at the trailing edge of the pulse received from the output of the control one-shot, the control voltage will be present at the output of the PD. The presence in the prototype feedback loop "FD-one-shot-GPN" allows you to control the duration of the pulse generated by the first one-shot, to equalize its duration with the transition time of the "saw" through zero level in the initial period of operation of the prototype device. Thus, it takes some time to enter the doubling mode, which makes this characteristic a significant drawback if it is used in frequency synthesizers used in transceiver installations with frequency hopping.

 The aim of the invention is to provide a device for doubling the pulse repetition rate, providing increased stability and reducing the time to form a doubled pulse repetition rate.

 This goal is achieved by the fact that in the known device for doubling the pulse repetition rate, including a single vibrator and an OR element, the output of which is the output of the device, additionally introduced the first and second elements NOT, the first and second elements I. The input of the device is connected to the input of the single vibrator, the first element NOT and the second input of the second element I. The output of the one-shot is connected to the second input of the first element AND and to the input of the second element NOT. The output of the first element is NOT connected to the first input of the second element I. The output of the second element is NOT connected to the first input of the second element I. The outputs of the first and second elements AND are connected to the inputs of the OR element.

 With such a combination of essential features, the proposed device, along with the frequency doubling, ensures the stability of the output pulse sequence with a short time for their formation, due to the absence of feedback circuits in the proposed device and the use of functionally complete AND, OR, and NOT elements in it.

 In FIG. 1 shows a block diagram of a doubling element; in FIG. 2 - time diagrams explaining the principle of operation of the proposed device; in FIG. 3 time diagrams explaining the principle of operation of the GPN and one-shot prototype.

 The device for doubling the pulse repetition rate (Fig. 1) consists of the first 1 and second 2 elements NOT, the first 3 and second 4 elements AND, one-shot 5 and the element OR 6.

 The input of the device is connected to the input of the one-shot 5, the first element NOT 1 and the second input of the second element And 4. The output of the one-shot 5 is connected to the second input of the first element And 3 and to the input of the second element NOT 2. The output of the first element is NOT connected to the first input of the first AND element 3. The output of the second element NOT 2 is connected to the first input of the second AND 4 element, the output of the first 3 and second 4 AND elements are connected to the inputs of the OR 6 element, the output of which is the output of the device.

 The elements that make up the proposed device can be implemented on standard integrated circuits, for example, the 155 series.

 The proposed device operates as follows.

The duty cycle pulse sequence T / τ-2, where T is the period of the sequence of pulses; τ pulse duration (Fig. 2a), is fed to the input of the element NOT 1 (Fig. 2b) and to the input of a single-shot 5, which forms a pulse of the same duration t, but with a delay of t / 2 (Fig. 2c). At the moment of simultaneous presence of the pulse duration at both inputs of the And 3 element, an impulse of duration τ / 2 will be formed at its output. At the same time, a pulse of duration τ / 2 will be generated at the output of the And 4 element at the moment of the presence of an invertible pulse and a pulse formed at the output of the one-shot 5. Thus, the OR 6 element, combining the sequences arriving at its input from the outputs of And, (Fig. 2 k, e, n) with a pulse repetition rate T / 0.5 τ, forms the output double pulse repetition rate
T / 0.5τ + T / 0.5τ = 2 (T / 0.5τ),
where 1 / 2T-F or 2F-1 / T.

 In the prototype, to generate a double pulse repetition rate, the PD generates a control voltage at the input of the first one-shot in the case when the time of arrival of pulses from the output of the second one-shot matches the transition time of the “saw” through the zero level. However, with a large repetition period of the clock pulses arriving at the input of the prototype device, the rise time of the sawtooth voltage increases. In this case, the stability of the double pulse repetition rate will depend on the moment of the saw’s transition through the zero level, which in turn is determined by the half-period of the synchronization pulses. To maintain stability, it is necessary to maintain the working section of the "saw" linear (Fig. 1). To do this, increase the supply voltage of the GPN, which determines the amplitude of the "saw". This method of maintaining stability becomes unacceptable in frequency synthesizers in transceiver installations with frequency hopping, as it leads to significant instability and distortion, the reasons for which are described above.

In the proposed device, the doubling of the input pulse sequence is carried out only by sequentially performing logical operations
multiplication, addition and negation, which allows you to get rid of maintaining the adjustable characteristics of the device at the required level and from the feedback circuit as a whole. This advantage allows the cascade connection of the proposed device and its use in frequency synthesizers in transceiver installations with frequency hopping.

Claims (1)

 A device for doubling the pulse repetition rate, comprising a single vibrator and an OR element, the output of which is the output of the device, characterized in that the first and second elements are NOT additionally introduced, the first and second elements AND, the input of the device is connected to the input of the single vibrator, the input of the first element and the second input of the second element AND, the output of the one-shot is connected to the second input of the first element AND and to the input of the second element is NOT, the output of the first element is NOT connected to the first input of the first element AND, the output of the second element is NOT sub is connected to the first input of the second AND element, the outputs of the first and second AND elements are connected to the inputs of the OR element.

Images