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ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING Radio station on 144 MHz, or How to make something out of nothing... (part 2). Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / Civil radio communications See the start here: "Radio station on 144 MHz..." Block diagram of the river. stations: where: BU - control unit; KN - buttons; IND - display unit; MF - frequency synthesizer; VCO - voltage controlled generator; TX - transmitter output stage; RX - receiver; MU - microphone amplifier; ULF - LF output amplifier. Not an unimportant question: how to program the processor and, most importantly, with what? Of course, I mean the microcontroller. The following will concern only the AVR family from Atmel, although it also produces other microcontrollers (such as the 8051 Intel, which only have all sorts of DACs and other devices on the chip or the most powerful 16/32-bit RISC processors in FPGA performance, which are unrealistic to solder at home) . First, you will need to know technical English, or at least a decent dictionary. To begin with, let's merge from the site (atmel.com, atmel.ru), the datashits section (datasheets are free, except for paper ones), the volume is 1,4 MB) a description of the cheapest microcontroller AT90S1200, the price for it in Novosibirsk is 120 rubles (probably then AT90S8515 price will be 851 rubles :), just kidding, they promised within 200 rubles). The processor purchased the cheapest one on purpose, in order to debug the core of the program in hardware, multiple corrections in the program and, accordingly, rewriting of FLASH are needed, and the number of cycles is still limited. Although, it wasn't worth the hassle. Descriptions in PDF format. The viewer can be merged on most sites or from a company, called Adobe Acrobat Reader, version 4.0 weighs 5 MB. The program is free. Let's read, think, and merge descriptions from more capacious microcontrollers, for example AT90S8515. Characteristics of microcontrollers:
Yes, FLASH holds guaranteed 1 write cycles, EEPROM 000 write cycles. Then let's merge the description of assembler commands (mnemonics) (Instruction_set, size 1,2 MB), i.e. which team does what. This description should be handy. Then we will merge the program for virtual process simulation (AVR Studio, volume 3 MB), it has a built-in assembler, compiler. Universal thing. It is highly recommended to study the examples of programming and building systems that are on the manufacturer's website and in the Appnotes directory after installing AVR Studio. The program is free. Then we will merge the program - the programmer, in order to sew the program into the FLASH memory of the processor and the data into the EEPROM. Atmel.com (atmel.ru also has one) has an ISP program. But, for some reason, she didn’t want to work :(, I had to use the AVReal program (I took it from chat.ru/~avreal/av114r6.zip, 30 kilobytes, as I understand it, it’s free). But she also couldn’t work normally with my copy processor (everything is not like that of people. Although everything is sewn / read correctly. The programmer consists of 5 wires and a connector, the circuit is in the archive with the program. Oh, eagle! No need to hot pull the connectors, you will burn the LPT port, turn off the power though Hint: what if powered from a computer, there are 5 volts, and 12 volts, and even a bipolar. Atmel produces a CD-ROM with programs, datasheets and a bunch of examples and other descriptions, it costs about 200 rubles, but I just heard it, I never saw it myself. Well, the Atmel Russian site has information on this CD-ROM, but it's kind of muddy. Here. How to program? First we erase FLASH, then we write a new my_programm.hex and my_data.hex into it, you don’t need to erase the EEPROM, just write the data there, it will be erased before that. Then we will start verification. Now let's think about the hardware, what to hang on which leg. The scheme is not given, it is simple - too lazy to draw, and it is a shame to scan a drawing by hand on a piece of paper. Here is a description of the findings.
The buttons are grounded. The quartz resonator with binding capacitors and wires for ISP are connected according to the diagrams given in the company documentation. Clock pulses can be taken from the generator in the synthesizer, but consider the operating frequency of the AVR, they work either up to 4 MHz or up to 12 MHz. By the way, the data and strobing buses of the indicator and the synthesizer can be combined, because. information is rewritten into the internal register of the synthesizer using a special output. Those. if there are not enough port pins, we hang everything in a heap, output information to the synthesizer, snap it in, and then shove the data onto the display. Well, the most crucial moment has come: writing a program, language - assembler. So: we will display the data on the indicator, display the data on the display and fall asleep by turning off the clock generator. This is so that the processor does not create unnecessary noise when scanning the keyboard / indicator. When we press the button, the low level through the diode will go to the interrupt input, the processor will wake up and start executing the external interrupt processing procedure. In it, let's see which button is pressed and do something, for example, increase the frequency by one step. Then we will output the new data to the synthesizer and to the display. That's it, let's return control to the main program, it will again put the processor to sleep. Do not forget that when switching from reception to transmission, you need to change the synthesizer division factor to a value equal to the intermediate frequency (I have an IF of 10,7 MHz), you can not touch the indication and you can not put the processor to sleep. Read the source for more details, the bare minimum was written and debugged in just two days. The program is debugged on a computer (AVR Studio, if you have any questions about it, write, we'll think about it). Interface. The program currently supports: only the “step up”, “step down” buttons at a step of 25 kHz. In the future: enable/disable repeater spacing, both -600 kHz and +600 kHz; indication of frequency reduction/increase in transmission with diversity; scanning up or down in frequency, through memory channels (selection by the “UP”, “DOWN” button, stop by opening the squelch); writing / reading memory cells; valkoder, switching grids. But, I'm afraid, everything will not fit in 1 kilobyte. Well, quite already for coolness: direct frequency dialing on a 10-button keyboard. It was the first option. And here is the second one. Connect the synthesizer to the LPT port instead of the processor. Do you need a diagram? What is hard to come up with? Okay, I had this when debugging the synthesizer:
I did not agree on anything, all the levels turned out to be TTL. Well, a small program in assembler that outputs data and goes to DOS. You can go further, draw a virtual control panel and send a noise suppressor signal to the LPT to stop scanning, but I didn’t pursue such a goal. But it's quite realistic, take DOS, Windows, OS / 2, * NUX and write under it, you can even use the audio path of a sound card as a microphone / output amplifier. What the hell is not joking, you look and the Russian WinRadio will appear, but I will not do this (yet). It is still desirable to screen and set the quartz to odd (such as 3,698 MHz), otherwise a bunch of lesions will appear during scanning, because the processor is active during scanning. There is such an idea: the receiver and the IF - the low-frequency path on the one hand, on the other hand the VCO and the output stage of the transmitter (I have a KT610, 200 mW), and the processor and display with buttons on the front panel p. stations. It’s just not clear where to put the synthesizer, on the one hand, long wires are not needed, and on the other hand, interference from its quartz. There is such an idea: to place the synthesizer near the VCO, and heat the quartz in a metal box with foam filling. And shove all this into a case from a Chinese radio, or an automobile CIB-shnoy river. stations. Indication with sequential input of information on three 561IR2. IRs are glued to the indicator, all connections are wired. An indicator with a common plus with all elements lit (`888) consumes 60 mA when powered by 5 volts. The indicator itself is connected to power through a +5 volt current-limiting resistor, but if desired (or insufficient brightness), you can hang it at +9 or even +12 volts. Keep an eye on the output currents of the microcircuits (5 mA per output), although RA9UCN (Vladimir, Mariinsk) swears that everything works, but I somehow feel uneasy about the triple overload in its design. For reference: RA9UWD (Igor, Yaya) powered the indicators from 6 volts and heated the IRs to 70 degrees, nothing burned out. IRs are powered by +5 volts. If power consumption is critical, you can modify the program so that after 5 - 6 seconds after changing the readings, the indication is extinguished. To ignite the element, you need to output a logical “0”, in order not to ignite - a logical “1” and probing. 8 pulses per digit, since the indicators are 7-bit, we will hang the remaining digit of the older microcircuit on “`”, the remaining two free ones can be used to indicate the spacing (there are a lot of luminous dots on this Chinese indicator, they indicated the range in the radio tape recorder). To be honest, 2 IR-ok are enough for indication: the apostrophe (144/145) is hung on the free output of the highest digit, the last digit is “5” or “0”, through diodes it is hung on the free output of the middle microcircuit. Or you can indicate the channel number, there are only 80 of them. Well, if it’s completely strained with IR2. If the indicator's common output sits on ground - it doesn't matter, we will invert the data stream, it is possible to change the character generator in hardware, but it's easier in the program (one hell, it is stored in EEPROM). After displaying information on the indicator, you can forget about it. Output speed - up to 2 MHz, faster 561IR2 start to fail. One comrade promises to give an LCD with a controller, but I'll put it on. Speaking of power: a synthesizer, a control unit - 5 volts (KREN5, you can hang it on each unit, now it is available in a small-sized version, well, just like KT209); receiver, microphone amplifier (half K157UL ?, dynamic microphone), VCO - 9 volts (bourgeois ROLL); transmitter output stage (on one transistor :), ULF (K174UN14) - 13,8 volts. A little note on the end. The first transistor after the VCO can be powered from +9 volts, and the next stages from +12 volts. Frequency modulation (or slightly phase), transistors, of course, operate in mode C. Buttons any 4 pieces, bourgeois small-sized from the same Chinese radio tape recorder are well suited. You can use a mechanical shaft-encoder, there are free-rotating, and there are switches with a clearly limited angle of rotation of the handle. These are at cheap CBS stations. Perhaps then I will put an optical shaft encoder from the mouse. And, despite the assurances of RA9UWD (Yaya, Igor), the use of simple (not thermally compensated) quartz in the synthesizer did not lead to a noticeable frequency shift at room temperature (about +20 degrees C). Of course, if you bring a hot soldering iron to a quartz resonator, then the frequency ran away by 100 - 120 hertz (10 MHz quartz was torn out of a dead HDD controller) at a frequency of 145 MHz. By the way, Alinco-DJ191 runs away in the same way if you go outside from a warm apartment (about +20 degrees C) (-35 degrees C). This is not very noticeable by ear when working with a voice. If stability is needed more (digital work), then you can put quartz heated in vacuum, which is used in the Mayak synthesizer, but you will have to recalculate the division coefficients (there is quartz at 2 MHz). Or look at how it was done in the Angara, there is thermal compensation and super power stabilization. I took SMD resistors and blocking capacitances from the controller from a dead CD-ROM. The inscriptions can be deciphered, or you can measure it with a C-shka. Resistor in the power supply circuit of the microcircuit (output?) Set sure! It is needed to eliminate the thyristor effect. The microcircuit is used in standard inclusion, SMD execution. If the conclusion? hang the LED, then when step-by-step tracing of the debugging program, it was clear that the data was falling out of the synthesizer register. On the first run, there is “0”, and on subsequent runs, the previous information is expelled. VCO from "Mayak" in a metal case filled with foam. RA9UWD (Yaya, Igor) will make his own VCO, he wants to put a single-chip synthesizer and a control unit on the AVR into the quartz mobile Viola (maybe we will publish it too). It is better to make two VCOs to reduce phase noise (see the description of 1015PL2, the tuning slope of 1 MHz per volt is declared there). Each VCO is tuned within 2 MHz: 144 - 146 MHz and 133,3 - 135,3 MHz. For example in Alinco-DJ191 one VCO covers 174 - 130 = 44 MHz!! Yes, plus the first IF 21 MHz, total 21 + 44 = 65 MHz i.e. 20 MHz per volt or am I missing something? Yes, even 20 MHz with 3 volts of power is already a lot. On the “Mayakovsky” GUNs, the voltage dangles before our eyes (measured with a digital C-shock), but what about Alina then? I don't understand why at all :) it still works. Scheme VCO from "Mayak":
The VCOs themselves are assembled on transistors VT1 and VT2 (generator with a common gate), through C11 and C12 they are loaded on R10. From which the signal is fed through the buffer to VT4 to the output amplifiers VT6 (the signal goes to the receiver and the output stage of the power amplifier) and VT7 (the signal goes to the input of the synthesizer chip). VCO switching is done on transistors VT3 and VT5, i.e. one is for receiving, the other for transmitting. Details: C1, C2, C4, C6, C13, C18, C19, C20, C21 - 1500 pF, C3, C5 - 3,6 pF, C7, C9 - 3,3 pF, C8, C10 - 15 pF, C11, C12 - 1 pF, C14, C15 - 12 pF, C16 - 22 pF, C17 - 10 pF. R1, R7, R8, R10, R13, R16, R18 - 15 kOhm R2 - 56 Ohm, R3, R4 - 2,2 kOhm, R5, R6, R12, R20 - 470 Ohm, R9 - 150 Ohm, R11 - 1 kOhm , R14 - 10 kOhm, R15 - 3,9 kOhm, R17 - 4,7 kOhm, R19 - 180 Ohm, R21 - 330 Ohm. Varicaps - KV109, VT1, VT2, VT4 - KP307, VT3, VT5 - KT315, VT6, VT7 - KT399. For example, the VCO circuit from Alinco-DJ191 (VCO - voltage controlled oscilator, voltage controlled oscillator) is given:
On Q301, the generator itself, Q302 is a buffer amplifier, the role of Q303 is unclear to me, it obviously pulls the VCO to another range by shunting L303 through C307 to ground. Because capacitance C307 (0,001 uF) at RF is blocking. Printed circuit boards were made like breadboards: one block - one board. Fiberglass - one-sided. Well, I'm too lazy to redraw them, scan them ... In addition, there is an idea to combine the boards of the control unit and the synthesizer. Author: Sergey Gimaev, RW9UAO; Publication: N. Bolshakov, rf.atnn.ru
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