Frequency divider by 5000. Scheme, description

Free technical library

ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
Free library / Schemes of radio-electronic and electrical devices

Frequency divider by 5000. Encyclopedia of radio electronics and electrical engineering

Free technical library

Encyclopedia of radio electronics and electrical engineering / Civil radio communications

Comments on the article

The use of a digital scale in the transceiver allows not only to improve the comfort of the operator when reading the frequency, but also in a simple way to significantly increase the stability of the GPA frequency using the CAFC system. The composition of the digital scale includes, as a rule, a quartz oscillator and a frequency divider, necessary to obtain accurate time intervals during which the pulses are counted. In principle, this generator can be excluded from the digital scale and simplified by taking advantage of the fact that the transceiver has its own quartz local oscillator. In this case, all pulse signals are automatically synchronized, since a common generator is used. In addition, the fewer generators in the device, the fewer harmonics and affected frequencies, and the design is simpler - there is an economy of radio components.

Many transceivers (such as the UW3DI) use a 500 kHz local oscillator. If its signal is applied to a digital scale, having previously divided its frequency by 5000, then we will receive pulses with a stable repetition rate of 100 Hz, which in most cases are needed to form a counting time interval.

Frequency divider by 5000
Fig. 1

A frequency divider with such a coefficient is easy to build on a K561IE16 binary counter according to the circuit shown in fig. 1. It uses significantly fewer microcircuits than common dividers with the same ratio on decade counters.

On the transistor VT1, an input amplifier-pulse shaper with a frequency of 500 kHz is assembled. The DD1 microcircuit (14-bit binary counter with serial transfer) has two inputs - setting the initial state R and counting C. The latter receives pulses from the collector of the transistor VT1. Their account occurs on falling drops (changes of a high logic level to low ones). The counter flip-flops return to their original zero state when a high logic level signal is applied to the R input.

The logical node AND on the elements DD2.1, DD2.2 and DD3.1 must have as many inputs as there are units in the binary representation of the division factor. In our case 5000₁₀= 1001110001000₂, and the inputs of the logical node must be connected to the outputs 2³ (8), 2⁷ (128), 2⁸(256), 2⁹ (512) and 2¹² (4096). Note that the exponents correspond to the ordinal number of the digit (starting from the least significant zero) in the binary representation of the division factor. In this case, the sum of the weights of the used bits is equal to 5000 - the given division factor. When the number accumulated by the counter reaches this value, the level at the output of the element DD3.1 and the input R of the counter becomes high, the counter is reset and the counting cycle starts from the beginning.

Similarly, on the K561IE16 chip, you can build a frequency divider with an arbitrary division factor, up to 2¹⁴-1 (16383). It should be borne in mind that its maximum operating frequency at a supply voltage of 9 V is 4 MHz (in fact, a little more). It changes in proportion to this voltage.

Frequency divider by 5000
Fig. 2

The K561IE16 chip has outputs from all counter triggers, with the exception of two with weights 2¹ (2) and 2² (4). If just such outputs are required to implement the desired division ratio, they can be organized by connecting another low-bit binary counter in parallel with the K561IE16 (DD1) counter. For example, as shown in fig. 2, one of the counters of the K561IE10 (DD4.1) chip. When working synchronously with the counter DD1, its outputs will have a weight of 2⁰ (1), 2¹ (2), 2²(4) and 2³(8)

Capacitor C2 is used to initially set the counter to its initial state when the power is turned on. Diodes VD2, VD3 and resistor R3 form an OR node, logically summing at the input R of the counter the zeroing pulses when the power is turned on and coming from the output of the DD3.1 element.

It should be noted that after turning off the power, the duration of the discharge of the capacitor C2 can reach several minutes. To reduce it, if necessary, we recommend connecting a 2 MΩ resistor in parallel with capacitor C1.

Author: Olga Leznaya

See other articles Section Civil radio communications.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Machine for thinning flowers in gardens 02.05.2024

In modern agriculture, technological progress is developing aimed at increasing the efficiency of plant care processes. The innovative Florix flower thinning machine was presented in Italy, designed to optimize the harvesting stage. This tool is equipped with mobile arms, allowing it to be easily adapted to the needs of the garden. The operator can adjust the speed of the thin wires by controlling them from the tractor cab using a joystick. This approach significantly increases the efficiency of the flower thinning process, providing the possibility of individual adjustment to the specific conditions of the garden, as well as the variety and type of fruit grown in it. After testing the Florix machine for two years on various types of fruit, the results were very encouraging. Farmers such as Filiberto Montanari, who has used a Florix machine for several years, have reported a significant reduction in the time and labor required to thin flowers. ... >>

Advanced Infrared Microscope 02.05.2024

Microscopes play an important role in scientific research, allowing scientists to delve into structures and processes invisible to the eye. However, various microscopy methods have their limitations, and among them was the limitation of resolution when using the infrared range. But the latest achievements of Japanese researchers from the University of Tokyo open up new prospects for studying the microworld. Scientists from the University of Tokyo have unveiled a new microscope that will revolutionize the capabilities of infrared microscopy. This advanced instrument allows you to see the internal structures of living bacteria with amazing clarity on the nanometer scale. Typically, mid-infrared microscopes are limited by low resolution, but the latest development from Japanese researchers overcomes these limitations. According to scientists, the developed microscope allows creating images with a resolution of up to 120 nanometers, which is 30 times higher than the resolution of traditional microscopes. ... >>

Air trap for insects 01.05.2024

Agriculture is one of the key sectors of the economy, and pest control is an integral part of this process. A team of scientists from the Indian Council of Agricultural Research-Central Potato Research Institute (ICAR-CPRI), Shimla, has come up with an innovative solution to this problem - a wind-powered insect air trap. This device addresses the shortcomings of traditional pest control methods by providing real-time insect population data. The trap is powered entirely by wind energy, making it an environmentally friendly solution that requires no power. Its unique design allows monitoring of both harmful and beneficial insects, providing a complete overview of the population in any agricultural area. “By assessing target pests at the right time, we can take necessary measures to control both pests and diseases,” says Kapil ... >>

Random news from the Archive

New material for the bone frame 09.02.2018

A diseased organ or tissue can be transplanted by taking a replacement from a donor - however, this is not possible with all organs. This has been done for quite a long time, but recently, doctors and biologists are increasingly trying to grow tissues for transplantation from scratch, right in the laboratory, and there are already absolutely amazing achievements (for example, a boy with epidermolysis bullosa literally grew new skin) .

And you can also do otherwise: to transplant to the patient not a ready-made organ, but a frame on which the body itself will complete the necessary tissues. Such a scaffold must, of course, be biocompatible and at the same time it must stimulate recovery processes. For example, bone scaffolds make it possible to restore the porous three-dimensional structure of damaged bones and their physiological functions, they provide an influx of nutrients to the site of damage, due to which the bone tissue successfully regenerates.

Researchers from the University of Helsinki and the Institute for Theoretical and Experimental Biophysics (ITEB) of the Russian Academy of Sciences have found a new, more efficient material for the bone scaffold by combining hydroxyapatite, gelatin, polypyrrole and mesoporous silicon oxide. Synthetic hydroxyapatite is widely used in bone tissue engineering - its chemical composition is similar to bone hydroxyapatite. However, despite its biocompatibility and the ability to stimulate bone regeneration, it has a strong drawback - it is too fragile. On the other hand, in the company of other compounds, it becomes stronger.

Another component of the new scaffold, silicon dioxide, is also able to activate bone mineralization; in addition, it can be used as a drug delivery vehicle and regulate the release of drugs at the right place with its help. The third component is gelatin: osteoblast cells are well associated with it, due to which bones grow. Finally, polypyrrole is needed to bind together hydroxyapatite, gelatin and silicon dioxide. It also has its drawbacks, but in combination with other materials it is quite possible to use it without fear that it will damage living bone tissue.

Other interesting news:

▪ Mat for effective cardiopulmonary resuscitation

▪ The longest-lived vertebrate identified

▪ Honor Earbuds 3i Wireless Headphones

▪ Expansion card QM2-2P2G2T

▪ To prevent headphone wires from getting tangled

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Grounding and grounding. Selection of articles

▪ article Organization of halts and overnight stays. Fundamentals of safe life

▪ article How old was the youngest mother in the world? Detailed answer

▪ Kindergarten teacher article. Standard instruction on labor protection

▪ article Generator on a photoresistor. Encyclopedia of radio electronics and electrical engineering

▪ article Charger with temperature compensation. Encyclopedia of radio electronics and electrical engineering

Leave your comment on this article:

All languages of this page

Home page | Library | Articles | Website map | Site Reviews