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Topic: Frequency counter

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	Frequency Counter Accuracy and Resolution - Radio-Electronics.Com
		Frequency counters are widely used for the measurement of frequency of radio frequency, RF, signals, or for that matter the frequency of any repetitive electronic signal.
		The resolution of a frequency counter is its ability to differentiate between two signals that are close to each other.
		The accuracy of a frequency counter is a little more difficult to determine as it is a function of a number of factors.
	www.radio-electronics.com /info/t_and_m/frequency_counter/counter_accuracy.php (881 words)

	Frequency Counter Methods (Site not responding. Last check: )
		The meter is adjusted until the cavity is tuned to the resonant frequency of the signal being measured.
		Frequency meters are capable of measuring frequencies in the range of 1 to 40 gigahertz, far exceeding the frequency limitations of the average frequency counter.
		The resonant frequency of the cavity is varied by means of a plunger that is mechanically connected to a micrometer mechanism.
	www.tpub.com /neets/book21/88f.htm (1661 words)

	Digital Frequency Counter from Sigma Instruments
		Digital Frequency Counter is a precision instrument capable of measuring a wide band of frequency.
		Frequency Counter can measure frequency as low as 1Hz, while the highest measurable frequency is 50MHz or 100MHz.
		Frequency is indicated in KHz or MHz by LEDs.
	www.sigmainstruments.com /p14_digital_frequency_counter.htm (193 words)

	Time and Frequency from A to Z
		Frequency drift may be in either direction (higher or lower frequency) and is not necessarily linear.
		Frequency mixers are commonly employed in frequency measurement systems (as shown in the graphic below), to convert a high frequency to a low frequency, and to obtain more measurement resolution.
		A simple frequency domain measurement involves directly counting and displaying the output frequency of the device under test with a frequency counter.
	tf.nist.gov /general/enc-f.htm (985 words)

	Using PIC timers to make a frequency counter.
		Making a frequency counter for frequencies up to 65.536kHz is easy as the counters in a PIC chip can count up to 65535 without overflowing.
		For the frequency counter interrupts are not used at all in either measurement of the input signal edges or measurement of the time period T.
		The trick with driving the multiplexed display for the frequency counter application is that the multiplex routine must work in a constant time.
	www.best-microcontroller-projects.com /frequency-counter.html (1285 words)

	PIC Frequency Counter with Frequency Lock
		Frequency reference is formed from the measured frequency itself after the delay defined by parameter 0Dh, when the number of the consecutive samples (defined by 0Eh) of measured frequency are within the +/-20 Hz.
		Next the frequency actual is subtracted from the reference and the difference is compared to value zero to calculate the deviation.
		It is nice to listen to the certain frequency on the band without continuous frequency corrections after a little while by means of the VFO knob.
	www.qsl.net /om3cph/counter/lcd/contribs/pic_flck.htm (1474 words)

	Frequency counter , Range 0 - 50 MHz or 30-1200MHz , small dimensions
		My effort was to build an easy but working frequency counter at the same time.
		The analog part is amplifying the input signal, the digital part is measuring the frequency and sending the measured data to the PC.
		Simply connect frequency counter to measuring device and you see the value of frequency online.You can use 15 frequency counters at the same time (or 15 other units).
	www.digital-measure.com /html/freq_counter.htm (362 words)

	Frequency Counter
		The counter is 24 bit and the 24 output are connected to shiftregisters.
		I have grown fond in the LMX2337 Frequency Synthesizer.
		Most often I divide the input frequency with 250 and set the frequency counter to measure under 0.5 sec, wich gives me the resolution of 500Hz and the uppdate will be 2 times/second.
	hem.passagen.se /communication/freqcount.html (863 words)

	Digg - 1 Hz to 50 MHz Frequency Counter
		Perhaps if you were making a transmitter in that frequency range and wanted to tune it.
		Although, you'd need something to calibrate the counter in the first place.
		Frequency counters are used for RF and audio tuning (as mentioned) and for debugging any project that emits a regular signal.
	www.digg.com /hardware/1_Hz_to_50_MHz_Frequency_Counter (599 words)

	Freq Counter Techniques
		A frequency counter is an excellent means of accurately determining the frequency of unknown signals, or to see if an oscillator or a multiplier stage in a receiver or transmitter is working.
		Due to the counter frequency response, it may favor some of these components over others as the counter may have much higher sensitivity at the favored frequencies.
		A counter coupled to the stage may show 107 MHz or 214 MHz as the output if its sensitivity is much higher at 107 or 214 MHz than 428 MHz, or may show a jumping reading or one that changes as counter coupling method or preamp sensitivity is varied.
	www.northcountryradio.com /Articles/counter.htm (1233 words)

	Jesper's AVR pages - Countermeasures
		Well, but the old counter is now somewhere in the shed, and as I now again needed a counter, I did a bit more modern design.
		The two 'HC590 counters are counting the input pulses and supplies the count to the 2313 on the databus.
		The counters are gated using the OC1 (Output Compare 1) signal from the 2313.
	www.myplace.nu /avr/countermeasures/index.htm (562 words)

	Using a Frequency Counter in Paranormal Investigations
		Input B is a nominal input for frequencies in the range 20MHz to 1.3GHz.
		It is important to remember that the counter will receive any frequencies with in the selected range and function (direct measure or period measure).
		If there are excessive frequencies being induced into the environment, you may be able to get a more accurate reading by using the period events filter.
	www.sgha.net /articles/frequencycounter.html (634 words)

	Frequency counter with PIC and 4- to 5-digit LED display
		The PIC firmware for the frequency counter can be downloaded from this link (includes hex file for all display variants and the assembly sourcecode).
		If your counter shows a strange frequency initially, enter setup mode to set the frequency offset to zero (it sometimes happens that PIC programmers don't erase the EEPROM where the frequency offset is stored).
		The offset frequency is the same as the intermediate frequency in this case, because the counter is usually connected to the receivers VFO (variable frequency oscillator).
	freenet-homepage.de /dl4yhf/freq_counter/freq_counter.html (3461 words)

	iB::Topic::What frequency counter?
		An old MFJ 249, the counter in my scope, and a 512Mhz from the eighties that I picked up for $5 at a hamfest.
		The scope counter works very well for what it is, but lacks precision.
		The reference oscillator in the counter will need to be a TCXO or even better, an ovenized oscillator that is kept at a constant high temperature.
	www.qrz.com /ib-bin/ikonboard.cgi?s=90baf7971c99f4a49e6584243a471b7a;act=ST;f=5;t=129408 (602 words)

	SR625 - Frequency Counter with Rubidium Timebase
		The SR625 Frequency Counter is a NIST traceable frequency counting standard for calibarating base stations, transmitters and many other types of communication systems.
		It combines the high resolution and wide variety of features found in the SR620 counter with the atomic accuracy of a rubidium timebase.
		The SR625 Frequency Counter consists of a frequency counter (SR620), a high-accuracy rubidium timebase (PRS10), and a 2 GHz input prescaler.
	www.thinksrs.com /products/SR625.htm (266 words)

	2313 Atmel Notebook
		The frequency of the wave is determined by taking the reciprocal of the period.
		In this case I stored each of the various digits representing the frequency on the stack (this is after a bunch of math followed by a binary to bcd routine).
		Another addition would be to scale the counter period depending upon the input frequency.
	www.tfs.net /~petek/atmel/freq/freq.htm (810 words)

	WiMo: Mini frequency counter, Surveillance receivers
		The Aceco frequency counter come complete with rechargeable batteries, wall charger (230V) and antenna (BNC jack) in a solid metal case.
		The counters are very sensitive, when using the supplied telescopic antenna a range of about 20m can be achieved (tested with a FC-2002 sensing a normal 2W handheld with rubber duck antenna).
		No problem with the FC-3002 and an additional scanner the frequency is immediately identified and sent to the scanner.
	www.wimo.com /frequency-counter-aceco_e.html (279 words)

	Frequency Counters, Handheld & Portable Frequency Counters \| TESSCO 800 472 7373 (Site not responding. Last check: )
		Useful for testing two way radios for frequency measurement in the field or using on the bench, the M1 is a full range 50Hz-2.8GHz frequency counter.
		The M1 BNC input may be switched from 50OHm to 1 Meg OHm for use with a scope or low pass audio probe for in-circuit measurement of test points and oscillators.
		The Optoelectronics Cub Frequency Counter is ideal for any two-way communication test application or general purpose frequency measurements.
	www.tessco.com /products/displayProducts.do?groupId=740&subgroupId=10 (458 words)

	lf253, Hardware: Frequency counter 1Hz-100Mhz with LCD display and RS232 interface (Site not responding. Last check: )
		The frequency of a sine wave or square wave signal is expressed as the number of oscillations per second.
		If you are only interested in frequencies up to 1.5Mhz (e.g to set up measurements for the frequency response of an audio amplifier) you can also build a simplified version of the counter an leave away the MAX903, 74F74 and the 74hc390.
		One could e.g image that you use this frequency counter to measure wind speed in remote areas or any other events that can be translated into digital frequencies.
	www.linuxfocus.org /English/September2002/article253.shtml (2588 words)

	Application Notes - Details (Site not responding. Last check: )
		The minimum rise and fall times of the input frequency are specified to be 10 ns, so the fastest clock rate the TMR0 can count is 50 MHz.
		Since the prescaler can be configured as a divide by 256 counter, the maximum resolution at which the input frequency can be measured is 16-bits.
		if the value is greater than 8-bits, the frequency and baud rate values have to be changed." 8-bit transmit and receive with no handshake, at baud rates from 1200 to 9600.
	www.microchip.com /stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en011033 (333 words)

	Frequency Counter / Frequency Meter, Free Construction article, schematics and Source Code
		The frequency counter circuit is built around a member of the PIC family of microcontrollers from Arizona Microchip.
		Underflows (frequencies less than 1Hz) or no signal at all are displayed as a single zero, and overflows (frequencies greater than 8MHz) are displayed as the letter ‘E’ (for error).
		The fragment of code increments the combined 16-bit counter by adding one to the low byte and if this causes the byte to roll over from 255 to 0 (since 255 is the largest number that can be stored in a single byte), then adding one to the high byte.
	www.apogeekits.com /counter_article.htm (4627 words)

	Digital Frequency Display Frequency counter for single conversion
		Frequency readout is in MHz (no engineering units are displayed as in other DFD1 models).
		These trimpots are used to input a frequency offset, usually equal to the IF frequency of the receiver or transmitter.
		Several circuits have appeared in the amateur and professional literature regarding adding prescalers to increase the range of frequency counters.
	www.aade.com /dfd1.htm (922 words)

	Frequency Counter
		The Laureate frequency counter can display frequency from 0.005 Hz to 1 MHz, rate in engineering units, and period (inverse of frequency).
		The Laureate frequency counter determines frequency by timing an integral number of periods over a specified gate time, and then taking the inverse of period.
		Exceptional flexibility is achieved for the Laureate frequency counter by programmable features and up to 5 plug-in boards in addition to the main board.
	www.laurels.com /frequency-counter.html (395 words)

	CW Microwave Counter Products
		Each of the microwave counter families offers its own special set of functions, one of which can bring the optimal solution to your CW microwave counter needs.
		Only Phase Matrix counters feature YIG-filtered inputs which provide unequaled performance in eliminating false readings, selecting signals in a multiple-signal environment and preventing burnout when excessive power is accidentally applied to the counters input.
		Phase Matrix counters can quickly and reliably select any desired signal in a multi-signal environment, even if it is not the highest level signal, thereby eliminating false readings and reducing measurement time.
	www.phasematrix.com /PM_Web/CWCounters.html (549 words)

	Digital Panel Meter: Frequency Counter, Frequency Counters, Digital Counters, Frequency Meter, Electronic Counter, ...
		The Laureate dual-channel frequency, rate and period meter is a basic operating mode of the Laureate counter with the FR signal conditioner board.
		The Laureate counter determines frequency by timing an integral number of periods over a specified gate time, and then taking the inverse of period.
		AC line frequency may be accurately measured to 50.0000 or 60.0000 Hz in a few line cycles.
	www.laurels.com /frequency.htm (1126 words)

	[No title]
		This frequency counter circuit is good for studying the basic principle of the frequency counter.
		IC3 is the counter as the center of this gear.
		To confirm the work of this counter, I connected this gear to the 10.24MHz crystal oscillator of the PLL radio.
	www.intio.or.jp /jf10zl/counter.htm (1449 words)

	Digital panel meter and counter for frequency, rate and period
		AC line frequency may be accurately measured to 50.0000 or 60.0000 in a few line cycles.
		If transducers with a frequency output are used, A*B allows horsepower to be displayed based measured torque and RPM, or based on force and velocity.
		The Laureate is compatible with all flowmeters which generate pulses at a frequency proportional to flow rate.
	www.flw.com /laurel/frequency.htm (1110 words)

	Frequency Counter / Frequency Meter Electronic Kit and Free Schematic
		A good use of the frequency counter is to calibrate other equipment.
		Attach a crystal microphone to the frequency counter and you have a guitar tuner.
		This frequency counter kit comes with a pre-programmed PIC, but if you like to learn about PIC source code, read and enjoy the free digital frequency counter / meter construction article and source code provided by MadLab.
	www.apogeekits.com /frequency_counter.htm (441 words)

	NorCal QRP Club - FCC-1 Frequency Counter Controller
		The exact frequency varies from unit to unit and some are faster than others.
		For those displays with a slightly lower clock frequency, the firmware didn't pause long enough to allow the LCD to complete its internal operations before the first character was sent, and it was garbled.
		Most counters I surveyed had various limitations, such as counting period, display resolution, etc. I decided that adding 1Hz resolution for precision measurements was an important feature to include.
	www.norcalqrp.org /fcc1.htm (1021 words)

	Frequency Counters for CB Radios
		The new FC390 Blue frequency counter uses the same style plug as the original FC390 or you can hard wire it to virtually any radio with the supplied wiring harness.
		The new FC390 red frequency counter uses the same style plug as the original FC390 or you can hard wire it to virtually any radio with the supplied wiring harness.
		The FC-390 is a universal frequency counter which indicates the frequency of the selected channel.
	www.premiere-electronics.net /store/freqcounters.html (191 words)

	Frequency Counter
		Store the output of the counters to the memory when the output of the time base is low.(i.e is to apply strobe only when time base is low)
		Output of the monostable multivibrator1 is used as strobe for the memory, so that when output of the astable of the goes from 1 to 0 the monostable triggers (i.e output of monostable1 will change from 0 to 1).
		Now the next monostable is used for resetting the counter We can use C1 output if the reset is active high and C for active low.
	www.geocities.com /njbibin/electronics/frequencycounter.html (542 words)

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