Wholesale online store of Chinese goods. Frequency meter circuit for power supply Frequency meter 1 50 MHz from China circuit

The main feature of this frequency meter:
A highly stable TCXO (Thermo-Compensated Reference Oscillator) is adopted. The use of TCXO technology allows immediately, without preheating, to provide the declared frequency measurement accuracy.

Technical characteristics of the FC1100-M2 frequency counter:

parameter	minimum	norm	maximum
Measuring frequency range	1 Hz.	-	1100 MHz.
Frequency readout resolution from 1 to 1100 MHz	-	1 kHz.	-
Frequency readout resolution from 0 to 50 MHz	-	1 Hz.	-
Input signal level for input "A" (from 1 to 1100 MHz).	0.2 V.*		5 W.**
Input signal level for input "B" (0 to 50 MHz).	0.6V		5 V.
Update period	-	1 time/sec	-
Testing of quartz resonators	1 MHz	-	25 MHz
Supply voltage/current consumption (Mini-USB)		+5V./300mA
Frequency stability @19.2MHz, at temperature -20С...+80С		2ppm(TCXO)

Distinctive features of FC1100 and FC1100-M2 frequency meters in particular:

	Highly stable reference oscillator TCXO(stability is not worse than +/-2 ppm).
	Factory calibration.
	Independent simultaneous measurement of two frequencies (Input "A" and Input "B").
	Input "B": Provides frequency measurement resolution of 1 Hz.
	Input "B" has a full-fledged analog input comparator threshold control (MAX999EUK), which makes it possible to measure, including signals noisy with harmonics, by adjusting the comparator threshold to a clean section of the periodic signal.
	Input "A" allows you to remotely measure the frequency of portable VHF radios at a distance of several meters, using a short antenna.
	Function of fast testing of quartz resonators from 1 to 25 MHz.
	Modern TFT color display with economical backlight.
	The manufacturer does not use unreliable electrolytic capacitors. Instead, modern high-quality SMD ceramic capacitors of significant capacities are used.
	Unified power supply via Mini-USB connector (+5v). Mini-USB power cord - supplied.
	The design of the frequency meter is optimized for integration into the flat front panel of any enclosure. Nylon insulating posts M3*8mm are supplied in the kit to provide a gap between the front panel and the printed circuit board of the frequency meter.
	The manufacturer guarantees that programmed aging technologies, which are widely used in modern technology, are not used.
	Made in Russia. Small batch production. Quality control at every stage of production.
	The best solder pastes, non-cleaning fluxes and solders are used in the production.

Dimensions of the printed circuit board of the FC1100-M2 device: 83mm * 46mm.
Display color TFT LCD with backlight (diagonal 1.44" = 3.65cm).
* Sensitivity according to DataSheet MB501L ("Input Signal Amplitude" parameter: -4.4dBm = 135 mV@50 Ohm respectively).
** The upper limit of the input signal is limited by the dissipation power of the B5819WS protective diodes (0.2W*2 pcs).

Back side of the FC1100-M2 counter

Scheme of the comparator / shaper of the input signal 0 ... 50 MHz.

Scheme of the frequency divider of the input signal 1...1100 MHz.

Brief description of FC1100-M2 frequency counter:

The FC1100-M2 frequency meter has two separate frequency measurement channels.
Both channels of the FC1100-M2 counter operate independently and can be used to measure two different frequencies simultaneously.
In this case, both values of the measured frequency are simultaneously displayed on the display.
"Input A" - (Connector type SMA-FEMALE) Designed to measure relatively high-frequency signals, from 1 MHz to 1100 MHz. The lower sensitivity threshold of this input is slightly less than 0.2 V., and the upper threshold is limited at the level of 0.5 ... 0.6 V. by protective diodes connected in anti-parallel. It makes no sense to apply significant voltages to this input, because voltages above the opening threshold of protective diodes will be limited.
The applied diodes allow dissipating power no more than 200 mW, protecting the input of the MB501L divider chip. Do not connect this input directly to the output of high power transmitters (more than 100mW). To measure the frequency of signal sources with an amplitude of more than 5 V., or a significant power, use an external voltage divider (attenuator) or a low-capacity transition capacitor (units of picofarads) connected in series. If it is necessary to measure the frequency of the transmitter - usually a short piece of wire is sufficient as an antenna, included in the frequency counter connector, and located at a short distance from the transmitter antenna, or you can use a suitable rubber band antenna from portable radios connected to the SMA connector.

"Input B" - (Connector type SMA-FEMALE) Designed to measure relatively low-frequency signals, from 1 Hz to 50 MHz. The lower sensitivity threshold of this input is lower than that of "Input A", and is 0.6 V., and the upper threshold is limited by protective diodes at a level of 5 V.
If it is necessary to measure the frequency of signals with an amplitude of more than 5 V, use an external voltage divider (attenuator). This input uses a MAX999 high speed comparator.
The input signal is applied to the non-inverting input of the comparator, and resistor R42 is also connected here, increasing the hardware hysteresis of the MAX999 comparator to a level of 0.6 V. The bias voltage is applied to the inverting input of the MAX999 comparator, from the variable resistor R35, which sets the level of operation of the comparator. When measuring the frequency of noisy signals, it is necessary to turn the knob of the variable resistor R35 to achieve stable readings of the frequency meter. The highest sensitivity of the frequency meter is realized in the middle position of the knob of the variable resistor R35. Turning counterclockwise - reduces, and clockwise - increases the threshold voltage of the comparator, allowing you to shift the threshold of the comparator to a noise-free section of the measured signal.

The "Control" button switches between the "Input B" frequency measurement mode and the quartz resonator testing mode.
In the testing mode of quartz resonators, it is necessary to connect the tested quartz resonator with a frequency from 1 MHz to 25 MHz to the extreme contacts of the "Quartz Test" panel. The middle contact of this panel - you can not connect, it is connected to the "common" wire of the device.

Please note that in the test mode of quartz resonators, in the absence of the tested quartz in the panel, there is a constant generation at a relatively high frequency (from 35 to 50 MHz).
Also, it should be noted that when the investigated quartz resonator is connected, the generation frequency will be slightly higher than its typical frequency (within units of kilohertz). This is determined by the parallel mode of excitation of the quartz resonator.
The testing mode of quartz resonators can be successfully used to select the same quartz resonators for ladder multi-crystal quartz filters. In this case, the main criterion for the selection of quartz resonators is the closest possible generation frequency of the selected quartz.

Connectors used in the FC1100-M2 frequency counter:

Power Supply for Frequency Counter FC1100-M2:

The FC1100-M2 frequency meter is equipped with a standard Mini-USB connector with a supply voltage of +5.0 Volts.
Current Consumption (300mA max) - Provides compatibility with most USB voltage power supplies.
Included is a cable "Mini-USB"<>"USB A", which allows you to power the frequency counter from any device that has such a connector (Personal Computer, Notebook, USB-HUB, USB Power Supply, USB Wall Charger) and so on.

For autonomous power supply of the FC1100-M2 Frequency Meter, the widely used "Power Bank" batteries with built-in Lithium-Polymer batteries, which are usually used to power equipment with USB connectors, are optimally suited. In this case, in addition to obvious convenience, as a bonus, you get galvanic isolation from the network and / or power supply, which is important.

*The main characteristics of the frequency meter - quartz meter*
Frequency range	1 Hz - 50 MHz
Support for measuring the frequency of quartz resonators	There is
Display Resolution Accuracy	5 bits (e.g. 0.0050 kHz; 4.5765 MHz; 11.059 MHz);
Automatic switching of frequency measurement ranges	There is
Auto power off when idle	15 s
Ability to program the output frequency, for the repair of transceivers and measuring equipment	There is
*General characteristics*
Display	LCD, five-digit red indicator
Nutrition	DC 5 - 9 V
Standby current consumption	11 mA
PCB dimensions	80mm x 53mm
Instrument weight	34 g
*Equipment*	kit for assembling a frequency meter 1Hz - 50MHz E0330 with the function of a tester for quartz resonators - 1 pc

Additionally:

When displaying results in kHz, the decimal point flashes;
When displaying results in MHz, the dot representing the fractional part lights up constantly;
Possibility to independently program input polarity.

Frequency meter - constructor up to 50 MHz for DIY assembly

Chinese frequency meter 1 Hz - 50 MHz E0330 allows you to measure the frequency of quartz resonators. A simple digital device allows you to measure the most used "quartz".

The quartz resonator tester is handy. Assembling the tester with a digital LED scale is no problem. Even a novice radio amateur can assemble a frequency meter with his own hands in a couple of hours. On the forums of radio designers, ordinary people recommend paying attention to this set.

The KIT frequency meter is inexpensive, assembled on a PIC on a microcontroller, which can take into account the frequency shift of radio receivers and transmitters when setting them up. When measuring the frequency of quartz at 10 MHz, the indicators will display the following: 10.001. A small relative error when measuring different quartz is preserved, and the comma in the number moves.

New convenient functions E0330

automatic switching of display resolution;
automatically variable measurement duration for accurate counting of pulses;
the ability to connect the device to the receiver generator and transmitter;
implementation in the firmware of the controller of the programming mode (setup mode), which has a menu with the choice of the desired function.

Frequency offset measurement

The frequency meter stores the measured values of the frequencies, which will be added or subtracted during further measurements. You can set the offset frequency to zero to display the measured frequency without offset. The shift value can be selected from a table stored in the controller's memory.

Energy saving mode

The power saving mode works as follows: if the frequency does not change for 15 seconds, it turns off. If the frequency value has changed by more than one value of the least significant digit - switching on. The mode can be controlled from the menu.

Ease of assembly of the E0330 frequency meter constructor

The KIT frequency meter is compact, neatly made and contains a panel for installing a microcontroller. This is necessary when programming with external devices. The ratings and seats of the elements are shown on the board.

I am a radio amateur

Frequency meter (1Hz - 50MHz).

The principle of operation of the described device (as well as other frequency meters) is: in counting the pulses that came to its input for a fixed period of time. Here are its main technical characteristics: the interval of the measured signal frequency is from 1 Hz to 50 MHz with a minimum input signal voltage of 0.5 V (depending on the shaper used). The digit capacity of the indicator is 8 characters, which allows you to indicate the frequency with a resolution of -1 Hz. The supply voltage is 9 V, and the current consumption depends on the indicators used, and the number of luminous discharges, in the author's version it reached 100 mA when all eights were indicated, and 50 mA when there was no input frequency.

Now, about how it was possible to achieve such characteristics. In the KR1878BE1 microcontroller used, the sixteen-bit timer-counter has an eight-bit prescaler and a three-bit overflow counter, which is 27 bits in total. Thus, the counter can count up to 134217727. The maximum measurable frequency is 50 MHz (obtained experimentally, for existing samples). The second interval is counted using software-organized cycles, during which a dynamic indication of previous readings is performed.

At the end of the count, the value of the measured frequency can be obtained by simply polling the registers only from a sixteen-bit timer-counter and a three-digit overflow counter. The data in the eight-bit prescaler is extracted using the count-to-overflow method. Single pulses are fed to the input of the prescaler, and when its overflow is detected (zeros in all bits), the value written in it is calculated equal to 256 (FF) minus the number of pulses supplied. After that, the binary number corresponding to the measured frequency is converted into binary-decimal, and then into the code of a seven-element indicator, while insignificant zeros are canceled in it, and at the next measurement this number is displayed on the display.

The device uses three three-digit high-brightness LED indicators from AON. In their absence, you can use any other LED indicators for the required number of digits, for example, the ALS318 series. Anodes of indicators through current-limiting resistors R8-R15 are connected to port B of the microcontroller. The cathodes are connected to the outputs of the decoder P3 K555ID10, the inflowing current of which in the state of logical 0 can reach 80 mA. The indication goes from right to left, i.e. the first digit is right according to the scheme. The ninth digit is not connected, however, if necessary, it can be used to display any service information.

To improve the stability of measurements, an external master oscillator is used, which is made on the elements P1.A-P1.C, powered by a separate stabilizer DA1. The software method of counting the measurement time allows the use of quartz resonators at any frequency. You only need to change the program cycles, and this is very simple, since all instructions in the microcontroller are executed in two cycles. The upper value of the reference frequency is 8 MHz, the lower value is determined by the fact that the output signal of the prescaler is synchronized by the processor clock frequency and cannot exceed 1/4...1/12 of its value, depending on the processor type. Unfortunately, these parameters are not specified in the documentation for the microcontroller. For a similar Microchip controller, the duration of the input signal should not be less than four processor cycles. Considering the eight-bit asynchronous prescaler, let's determine the minimum reference frequency: 50,000*4/256 = 781.25 kHz. Those. you can use quartz from 1 to 8 MHz.

The frequency meter is assembled on a breadboard measuring 30 x 72 mm. Connections are made by surface mounting with MGTF wire. The view with the indicator removed is shown in the photo.

A correctly assembled frequency meter after switching on should show the number 87654321 on the display for 1 second, and then go into counting mode, indicating zero in the first digit in the absence of an input signal. If there is no indication, check for the presence of a clock signal. Then you need to make sure that the scanning code is fed to the decoder inputs, from port A. Input 8 of the P3 chip must be connected to a common wire, otherwise its outputs will be closed. In addition, you can try to perform an external reset by short-circuiting the terminals of the capacitor C3 for a short time.

To check the operability of the frequency meter, you can apply a signal from the clock generator to the input of the microcontroller by connecting the output of the element P1.C to the input P1.B. The indicator will show the number of program delay cycles, i.e. the time during which the input frequency is measured (this value has nothing to do with the actual frequency of the master oscillator). The frequency meter is calibrated using an external (industrial) reference generator.

You cannot apply the measured signal directly to the microcontroller timer pin (PA4/TCLC), since this pin works both as an input (in measurement mode) and as exit!(in counting mode). In order to prevent overload and possible damage to the device elements, a current-limiting resistor R6 is included at the input.

The program that controls the microcontroller is very simple, it is easy to upgrade or add new functions. The full author's version is posted on the ftp-server of the journal at: ftp.paguo.ru/frequency/f.mic. and you can also watch it here f.mic

The description of the KR1878BE1 microcontroller can be found on the Internet at the manufacturer's website. Unfortunately, the documentation contains errors in the pinout of the microcontroller and the description of the TESSA compiler. Commands ctc, ctz, ctn, ctie should be clc, clz, cln, clie instead. When programming the microcontroller, you should turn on the external generator mode at a frequency from 500 to 8000 kHz.>

Frequency meter 1Hz-50MHz, quartz resonator tester

Set for assembling a frequency meter with a range of measured frequencies 1Hz-50MHz.
Also, the board can work in the mode of a quartz resonator tester.

The circuit can only measure positive polarity signals,
in case you want to measure the frequency of a bipolar signal
- you need to make an additional input stage for the frequency meter.

Frequency measurement ranges are determined automatically.
If the frequency value is displayed in kHz - the separating dot blinks,
if in MHz - glows constantly. Also, the circuit can make measurements with
taking into account the frequency offset that will be added or subtracted from
measured value.

Characteristics:

Quartz frequency range 4MHz to 27MHz
The range of measured frequencies in the frequency counter mode 1Hz ... 50MHz
Supply voltage 5...9 V
Used microcontroller PIC16F628
Case size 71x54x17 mm

Equipment:

1x Frequency counter 1Hz-50MHz, crystal tester as a kit
for self-assembly (unsoldered)

collected 1000 rub.

Frequency meter with crystal tester function Component set
for assembling a frequency meter with the function of a quartz resonator tester.
Simple and inexpensive, based on PIC microcontroller
with the ability to take into account the frequency shift of superheterodyne
receivers with a five-digit LED indicator,
convenient and intuitive. Functions Display resolution automatically
switchable to ensure maximum reading accuracy
with a 5-digit indicator. It also changes the duration automatically.
measurement (gate time) during which the pulses are counted on
input If the frequency meter is used for measurements in shortwave
receivers or transmitters, you may need to add or subtract
the value of the frequency shift from the measured frequency. Offset frequency
in many cases equal to the intermediate frequency, since the frequency counter
usually connected to the receiver's variable frequency oscillator.
To measure the oscillating frequency of a quartz, simply connect it to the jack
with the name "Tested Quartz" Main features: - Range
frequency measurements: 1 Hz - 50 MHz - General purpose quartz measurement
in the generation frequency in the range: 1 MHz - 50 MHz - Automatic
range switching - Programmable settings for added and
the subtracted value of the frequency shift during settings and measurements
in VHF receivers and transmitters. - Power saving mode when powered
from an independent current source - It is possible to use 5V from the USB interface
- Minimum number of components, easy assembly and setup

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