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M3 FPM-1 Features
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The M3 Univeral Frequency Counter modes and features:
- The FPM-1 has two inputs for frequency measurements between 2 Hz and 1.3 GHz with three selectable gate times of 100 mSec, 1 sec, and 2 sec. Using reciprocal counting, the FPM-1 provides true 7-digit resolution of the displayed frequency with a 1 or 2 second gate time. Using this technique, both the opening and closing of the main gate are synchronized with the input signal so that only completed cycles are counted. This means that the +/-1 input cycle error typical in conventional counters is eliminated. The resolution is therefore dependent only on the measurement time. What does all of this mean? It means that frequencies below 1 MHz will still be displayed with full 7 digit resolution. As an example, in measuring a typical PL tone of 151.4 Hz, a conventional counter would display either 151 or 152 Hz, or toggle between the two. The FPM-1 would display 151.4000 Hz. Click here for a graphical comparison of conventional versus reciprocal counting by Michel Waleczek.
- Besides frequency, the FPM-1 will also perform period measurments between 500 ms and 10 ns. As in the frequency counting mode, gate time determines the resolution and speed of measurement.
- The FPM-1 will measure the pulse width on square wave signals greater than 10 uS and less than 500 mS. The resolution of measurement is 0.2uS. Gate times have no effect on the measured results. Measurements can be selected to trigger on either the positive or negative edge of the pulse.
- The FPM-1 has an event counting (or Totalize) mode and counting can be started, stopped, restarted and reset from the on-screen menu.
- The FPM-1 will measure duty cycle to within 0.01% for signals above 20uS or a frequency below 50 KHz. This measurement is performed by first measuring the positive pulse and then the negative pulse. The duty cylce value is then computed from these two measurements.
- The FPM-1 has 10 user programmable memory slots where measured frequencies may be stored or frequencies may be entered manually through the FPM-1 keypad. These stored frequencies can then be used to implement the advanced features of the FPM-1 which permit offset and relative measurements between a stored frequency and an input frequency. These advanced features include;
1) display of the the input frequency minus the stored, or offset, frequency (Freq - fo)
2) display of the stored, or offset, frequency minus the input frequency (fo-Freq)
3) display of the input frequency plus the stored, or offset, frequency (Freq + fo)
4) Relative measurements between the input and stored frequency ([Freq -fo]/fo). The value displayed will either be in PPM (parts per million) if the absolute value is below 1000 ppm or expressed as a percentage with a maximum value of 999.9999%
These are very useful functions when there is a need to measure oscillator drift or when using the FPM-1 as a digital readout for transceivers.
The M3 RF Power Meter modes and features:
- RF Power measurement from +16 dBm to -72 dBm between 1 and 500 MHz with +/- 1 dBm accuracy. Usable to 800 MHz with reduced accuracy.
- Above 10 MHz, the FPM-1 RF Power Meter has built in frequency compensation in the firmware.
- Readout is selectable in either dBm or mW.
- 9 user programmable memory slots to store and recall external attenuator/amplifier values between -49.9 and +49.9 dBm. When in use, the display indicates either ATT (negative values in memory) for external attenuators or AMP (positive values in memory) for external amplifiers.
- Display resolution to 0.1 dBm.
SPECIFICATIONS:
INPUT CHARACTERISTICS (CHANNEL 1)
Range: AC coupled 2 Hz to 100 MHz Maximum, typical 90 MHz
Sensitivity: 20 mV rms sine wave 2Hz to 50 MHz
30 mV sine wave 2Hz to 70 MHz
40 mV sine wave 2Hz to 100 MHz
Impedance: 1 Meg ohm nominal shunted by less than 44pF.
Maximum Input Level:
2 Hz to 2 kHz 400V [DC + AC (rms)]
above 1 MHz derated to 10Vrms
INPUT CHARACTERISTICS (CHANNEL 2)
Range: AC coupled 50 MHz to 1.3 GHz
Sensitivity: 20 mV rms sine wave from 50 MHz to 300 MHz
50 mV rms sine wave from 300 MHz to 1.3 GHz
Impedance: 50 ohm nominal
Maximum Input Level: 1V rms 50V DC
INPUT CHARACTERISTICS (POWER INPUT)
Dynamic Range: 70dB minimum, 88dB typical
Input Range: -72 dBm to +16dBm typical
Resolution: 0.1 dBm
Accuracy: ±1.5dBm minimum with continuous sine wave input at 50 ohms, ±1 dBm typical (f < 500MHz)
Impedance: 50 ohm
Maximum Input Level: +20dBm
Specifications are dependent on calibration accuracy
FREQUENCY:
Range: 2 Hz to 1.3 GHz
Resolution: 1 µHz to 1 kHz depending upon gate time and input signal.
PERIOD:
Range: 12.5 ns to 500 ms
Resolution: 10-5 ns to 1µs
PULSE WIDTH:
Range: 8µs to 500ms
Resolution: 200ns
DUTY CYCLE:
Range: 0.00% to 99.99%
Resolution: 0.01% (f<500Hz)
Resolution: 0.1% (f<5kHz)
Maximum frequency: 60 kHz
Accuracy: ± 60 × 10-6 × f (Hz) (%)
TOTALIZE:
Frequency: 2Hz to 80 MHz typical
Resolution: ± 1 count
Accuracy: ± 1 count
TIME BASE:
Type: TCXO
Frequency: 20 MHz
Internal counting frequency: 5 MHz
Aging Rate: < ±3 ppm first year < ±1ppm thereafter
Temperature Stability: typically < 2 ppm from 10°C to 60°C
GENERAL:
Display: LCD 2 lines X 16 characters with backlight
Gate Time: 100ms, 1s or 2s
Operating Temperature: 0° to 50°C
Power Requirements: 9V DC to 15V DC; maximum 200mA
Dimensions: 6.125" × 4" × 1.5"
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