Fluke PM6685-051 - Very High Stability Oven Timebase

Cal lab performance in the field

With 10 digits per second resolution, plus overflow (11th and 12th digits), it delivers high accuracy measurements instantly. The standard timebase offers a stability of better than 5E-7 per month, and better than 5E-11 per month with the PM 6685R Rubidium Counter.

Built in capabilities simplify tricky measurements

The PM 6685"s built-in intelligence eliminates a lot of button pushing. Just plug it in, and it automatically selects optimum trigger level and input sensitivity for excellent noise immunity.

Analog bar graph

The analog bar graph displays signal strength and input sensitivity to assist instrument setup and RF tuning applications.

300 MHz basic input range; options for 2.7 GHz and 8 GHz.

Measurement functions

Frequency, Burst Frequency, Period A, Ratio A/E C/A, Pulse Width A, Duty Factor, Totalize A.

Auxiliary functions

External Arming, External Gate, Nulling/Frequency Offset.

Options & accessories

External Reference Multiplier (1,5,10 MHz), GPIB Interface, Battery Unit.

Calibration Instruments   >   Time and Frequency Instruments   >

PM 6685 Universal Frequency Counter

Measurement Functions Optional TimeBase Input and Output Specifications Auxiliary Functions Optional Pre-Scalers External Reference Options (Battery Unit PM 9623) Options (GPIB PM 9626/02) Other Functions Mechanical Data Measurement Functions Measurement Functions   Frequency, Burst Frequency, Period, Ratio f1/f2, Pulse Width, Duty Factor, Totalize A Frequency A, C Input A: 10 Hz to 300 MHz Input C (Optional Input Pre-Scaler): PM9624: 100 MHz to 3.0 GHz   PM9638: 300 MHz to 8.0 GHz Resolution: 10 digits/s measurement time Burst Frequency A Frequency range: 100 Hz to 80 MHz PRF range: up to 1 MHz Burst duration: 0.5 μ to 1.5 s,min. 3 cycles in burst Burst Frequency C Frequency range: 100 MHz to 8GHz PRF range: up to 1 MHz Burst duration: 0.5 μs to 1.5 s Period A Range: 3.3 ns to 100 ms Resolution: 10 digits/s measurement time Ratio A/E, C/A Range: 10 -9 to 10 9 Frequency range: Input A: 10 Hz to 300 MHz (prescaling factor 4)   Input E: 10 Hz to 80 MHz   Input C: See input C frequency range Pulse Width A Range: 6 ns to 10ms Frequency range: 50 Hz to 60 MHz Voltage range: 100 mV p-p to 70 V p-p Duty Factor A Range: 0 to 1 Frequency range: 50 Hz to 60 MHz Voltage range: 100 mV p-p to 70 V p-p Totalize A   Event Counting on A with manual start and stop Range: 0 to 10 14 Frequency Range: 0 to 100 MHz Optional TimeBase Standard: PM6685/-1- (Non -Retrofit) Calibration adjustment tolerance* * * at +23ºC ± 3ºC: < 1 x 10 -6 Uncertainty due to:   Aging /24 hr: N/A* Aging /month: < 5 x 10 -7 Aging /year: < 5 x 10 -6 Temperature Stability (reference temp at +23ºC): 0-50ºC: < 1 x 10 -5   20ºC -26ºC: 3 x 10 -6 Line voltage variation of ±10%: < 1 x 10 -8 Power On Stability: Not Specified Total Uncertainty* * * * at 2σ (95%) confidence   interval and at 23ºC ± 3ºC: After 1 Year Cal interval < 7 x 10 -6   After 2 Year Cal interval < 1.2 x 10 -5 Total Uncertainty* * * * at 2σ (95%) confidence   interval and at 0-50ºC: After 1 Year Cal interval < 1.2 x 10 -5   After 2 Year Cal interval < 1.5 x 10 -5 OCXO: PM6685/-5- (PM9691) Calibration adjustment tolerance* * * at +23ºC ± 3ºC: < 2 x 10 -8 Uncertainty due to:   Aging /24 hr: < 5 x 10 -10 * * Aging /month: < 1 x 10 -8 Aging /year: < 7.5 x 10 -8 Temperature Stability (reference temp at +23ºC): 0-50ºC: < 5 x 10 -9   20ºC -26ºC < 6 x 10 -10 (typical values) Line Voltage variation of ±10%: < 5 x 10 -10 Power-on stability: 1 x 10 -7 Deviation versus final value   after 24 hr on time, after a warm-up time of: 15 min Total Uncertainty* * * * at 2σ (95%) confidence   interval and at 23ºC ± 3ºC: After 1 Year Cal interval: < 9 x 10 -8   After 2 Year Cal interval: < 1.5 x 10 -7 Total Uncertainty* * * * at 2σ (95%) confidence   interval and at 0-50ºC: After 1 Year Cal interval: < 1 x 10 -8   After 2 Year Cal interval: < 2 x 10 -7 OCXO: PM6685/-6- (PM9692) Calibration adjustment tolerance* * * at +23ºC ± 3ºC: < 5 x 10 -9 Uncertainty due to:   Aging /24 hr: < 1 x 10 -10 * * Aging /month: < 3 x 10 -9 Aging /year: < 2 x 10 -8 Temperature Stability (reference temp at +23ºC): 0-50ºC: < 2.5 x 10 -9   20ºC -26ºC: < 4 x 10 -10 (typical values) Line Voltage variation of ±10%: < 5 x 10 -10 Short term stability: (root Allan Variance)   T = 1 s: 5 x 10 -11   T = 10 s: 5 x 10 -12 Power-on stability: 5 x 10 -9 Deviation versus final value   after 24 hr on time, after a warm-up time of: 10 min Total Uncertainty* * * * at 2σ (95%) confidence   interval and at 23ºC ± 3ºC: After 1 Year Cal interval: < 2.5 x 10 -8   After 2 Year Cal interval: < 5 x 10 -8 Total Uncertainty* * * * at 2σ (95%) confidence   interval and at 0-50ºC: After 1 Year Cal interval: < 2.5 x 10 -8   After 2 Year Cal interval: < 5 x 10 -8 * N/A: Not discernible, neglectable versus 1°C temperature variation. * * After 14 days continuous operation * * * Calibration Adjustment Tolerance: Is the maximal tolerated deviation from the true 10MHz frequency after a calibration. When the reference frequency does not exceed the tolerance limits at the moment of calibration, an adjustment is not needed. * * * * Total uncertainty: Is the total possible deviation from the true 10MHz value under influence of frequency drift due to aging and ambient temperature variations versus the reference temperature. The operating temperature range and the calibration interval are part of this specification. Input and Output Specifications Input A Frequency Range: 10 Hz to 300 MHz Coupling: AC Impedance: 1 MΩ//25pF or 50Ω, VSWR < 2:1 Sensitivity (SineWave): 10 mV rms, 10 Hz to 50 MHz   15 mV, 50 MHz to 100 MHz   20 mV, 100 MHz to 150 MHz   30 mV, 150 MHz to 200 MHz   50 mV, 200 MHz to 300 MHz Pulse: 50 mV p-p, 3 ns minimum pulse width Dynamic Range: 30 mV p-p to 70V p-p Manual Trigger Sensitivity Range:     10 mV rms to 10 Vrms, variable in 3 dB steps, indicated on bar graph Trigger Level: Selectable for optimum triggering on   waveforms with duty factors of <0.25, 0.25 to 0.75 and   0.75 Trigger Slope: Positive or Negative Auto Trigger   Automatic setting of input signal conditioning circuits for   optimum triggering on different amplitudes and   waveforms Frequency: Minimum 50 Hz Sensitivity Range: 10 mV rms to 25V rms Signal Monitor   A bar graph displays actual input signal level in 3 dB   steps, 10 mV rms to 10 Vrms Low Pass Filter   100 kHz nominal 3 dB point   Minimum 40 dB attenuation at 1 MHz Damage Level 1 MΩ Impedance: 350V (DC + AC peak) at DC to 440 Hz, falling to 12 Vrms   at 1 MHz and above 50 Ω Impedance: 12 V rms Auxiliary Functions External Arming/External Gate   External signal on input E can be used to inhibit start   and/or stop triggering   Stop arming is not applicable to Pulse Width and Duty   Factor measuring modes Start Arming Delay   OFF or 200 ns to 5s in 100 ns steps Nulling/Frequency Offset   Nulling enables measurements to be displayed relative to   a previously measured value or any value entered in via   front panel keys Optional Pre-Scalers Input C (PM 9624) Frequency Range: 100 MHz to 3.0 GHz Pre-Scaler Factor: 64 Sensitivity: 20 mV rms to 12V rms, 100 to 300 MHz   10 mV rms to 12V rms, 0.3 GHz to 2.5 GHz   20 mV rms to 12V rms, 2.5 GHz to 2.7 GHz   100 mV rms to 12V rms, 2.7 GHz to 3.0 GHz Amplitude Modulation: DC to 0.1 MHz: Up to 94% depth   0.1 to 6 MHz: Up to 85% depth   Minimum signal must exceed Input Sensitivity Impedance: 50Ω nominal, ac coupled, VSWR < 2.5:1 Damage Level: 12V rms pin diode protected Connector: Type N Female Input C (PM9638) Frequency Range: 3 MHz to 8 MHz Prescalar Factor: 256 Operating Input Voltage Range: 300...500 MHz: -21...+30 dBm   0.5...3 GHz: -27...+30 dBm   3.0...4.5 GHz: -21...+30 dBm   4.5...6.0 GHz: -15...+30 dBm   6.0...8.0 GHz: -9...+30 dBm Impedance: 500 Ω nominal, AC coupled, VSWR <2:1 Max Input Voltage Without Damage: 7 V RMS, pin diode protected Damage Connector: Type N female External Reference Input D   The use of external reference is indicated on the front   panel display Input Frequency: 10 MHz   with optional reference multiplier PM 9697 Voltage Range: 200 mV rms to 10V rms Impedance: Approximately 1 kΩ, ac coupled Input E   Used in ratio A/E and external arming / gating modes Frequency Range: DC to 80 MHz Pulse Width: 6 ns minimum Slew Rate: 2V/μs minimum Trigger Level: TTL level, 1.4 V nominal Trigger Slope: Positive or Negative Impedance: Approximately 2 kΩ, dc coupled Damage Level: ±25V peak Reference Output G Frequency: 10 MHz, Sine Wave Output: 0.5 V rms into 50Ω load, > 0.7 V rms into hi   impedance load, Ac coupled Options (Battery Unit PM 9623) Battery Unit (Option PM 9623)   The PM 9623 is a rechargeable battery unit for mounting   inside the counter Battery Type   Sealed lead-acid cells Battery Capacity   at 25ºC Standby Mode: Typically 20 hours with Oven Time Base Operating Mode:     Typically 3 hours without options, 2.5   hours with Oven Time Base, and 2 hours with Oven Time Base and Input C Recharge Time   Typically 8 hours in standby mode Battery Protection: Overcharge and deep discharge protection External DC: 12V to 24V via socket on rear panel (16V   to 24V to charge internal battery) Line Failure Protectio