Precision Crystal Oven Time-base Type 1 (OCXO) for Fluke Philips PM66xx Counters For Sale
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Precision Crystal Oven Time-base Type 1 (OCXO) for Fluke Philips PM66xx Counters:
$84.00
Time-base Type 1 (for PM66xx type counters, s. description):The Fluke / Philips family of counters PM66xx manufactured in Europe (i.e. PM6674, PM6680, PM6681, PM6685 etc) is well known throughout the world and quite popular as measuring instruments. The well known brand, features and the high precision (min 10+x digits resolution) are at least some of the reasons. But the true heart of a counter is the precision and accuracy of its time-base independet of the number of digits shown.This counter family is equipped as a standard with a very basic XO time base, tune-able by a variable capacitor to relatively low precision and mediocre drift parameters. Optional time base modules have been offered in the past (PM9679, PM9690, PM9691 etc.) but seem not to be available any more ore are not up to the task, if a high accuracy time-base is needed, especially if one of the GHz options are in use. Exceptions: Units employing a Ruofferium oscillator (R) as a factory installed standard. Note: Comparable commercial offerings for this type of module my cost up to 10 times more as new for current measuring gear.For the existing time base option/slot position a plug-able and calibrate-able OCXO based high precision time-base module of highest standards (s. data sheet OCXO, specifications in ppb, 1 ppb = 0.001 ppm, ppm = parts-per-billion) has been developed. The excellent specifications (long term drift, phase noise, mechanical stability etc.) of the OCXO used are listed in the manufacturers data sheet (s. pictures and link at end of text). The OCXO features a SC-cut crystal (S(tress)C(ompensated)-cut, 2 axes rotation), which improves especially on mechanical stability, long term drift, phase noise and other parameters (s. document link at end of text). The OCXO shows improved specifications typically meeting at least or surpassing those of the original time-base modules PM9697, PM9690, PM9691 etc. As is well know, a pre-conditioned (used) crystal features lower drift and improved stability compared to a brand-new unit, which is the main reason why one of those had been selected for this time-base. The OCXO (manufacturing date: 2006 or younger) had been tested before usage and is in good condition. The time-base module as a whole is made in Germany and described as *new*.The double sided FR4 PCB (purple solder mask, thickness 1.6 mm, industrial made) is of high quality and features gold plated (solder-)contact areas. Gold plated test pads allow for checking of individual voltages. The module communicates with the counter\'s electronics through the existing 10-pole connector provided for a time-base option module. The original PCB layout of this version is the work of Dan Watson. The module replaces any existing time-base module already in place. It uses the same M3 screw / washer(s) / nut(s) as the original module for mounting. Mounting hardware (screw/washers/nut) have to be supplied by the buyer. The mounting height of the module stays at or below the original modules height, thus the optional GPIB-option and / or accu-pack option may be used. The module can be calibrated by the buyer, if needed. Installation instructions are included.
=> Please note, that the mounting position may vary, depending on the individual type unit. Shown: PM6685.
Note: The original basic crystal oscillator has to be deactivated as described in the owners manual of the counter, the same way as is been needed, when installing any of the original time-base modules.The gallery picture \"Counter display with 2-digit overflow (10+2)\" shows as an example a momentary indication of the 10 MHz reference frequency : +0.0006 Hz !Technical data OCXO (see manufacturers spec sheet):
Phase noise (+/- 10 kHz): -155 dbc/Hz
Frequency stability, referred to:
- Temperature (-10°C / +70°C reference 25°C): typical +/- 5ppb, max +/- 10ppb
- Input (+/- 5%): +/- 5ppb
- Load (+/- 10%): +/- 1ppb
Aging:
- per day (typical): +/- 1ppb
- 1st year (typical): +/- 100ppb/year (less after that)
Short term stability:
- 0.1 s (Allan deviation, in still air): max +/- 0.01 ppb
- 1.0 s (Allan deviation, in still air) : max +/- 0.01 ppb
Warm-up time (to +/- 50 ppb at 25°C to frequency at 30 min): 4 min.
Note: 1 ppb @ 10 MHz = 0.01 HzThis time-base variant uses the existing Vref output of the OCXO (internally stabilised by a Zener diode).The time-base module features its own high quality, high efficiency and low heat dissipation DC-DC power supply on board, extensively filtered on either side. It filters and stabilizes additionally the counters internal supply voltage. It supplies power to the OCXO and its electronics, which is been used for tuning the OCXO to the desired frequency. The close proximity of both, the power supply and the OCXO, allows for good thermal tracking. The adjustment of the OCXOs frequency fine tuning is handled using the OCXOs own Vref output, stabilized inernally by a Zener diode, through an adjustable precision multi-turn cermet trimming-resistor with low temperature coefficient. Additional filter capacitors are been installed for buffering the supply and tuning voltages.
The buyer may easily exchange the OCXO for other types after adapting the component selection accordingly, because the OCXO uses a standard casing and layout like it\'s been employed by other manufacturers also (s. data sheet). Excerpt from data sheet DC-DC-converter:
Voltage regulation: input (typical): +/- 0.2% / output (typical): +/- 0.4%
Noise level (typical): 20 mVpp (12/24VDC input voltage)
Temperature coefficient (typical): +/- 0.015%/°C referenced to output voltageThe module has been manufactured in modern hybrid technology (SMT and Through-Hole) and is ready to be installed and run as provided. The electrolytic capacitors (brand-name manufacturer) are of the \"low ESR\" type with increased temperature range.The offered time-base module had been tested and adjusted in 3 steps:
- initial inspection and testing of the OCXO, rough definition of the needed tuning voltage (marking: red, time period appr. 1 hour)
- inspection and functional testing plus check for adjustability of the complete module on a test fixture (marking: yellow, time period appr. 5 hours)
- multi-stage adjustment in a Fluke / Philips test counter (PM6685) as one of the listed units of the PM66xx counter family (marking: green, time period appr. 24-48 hours)
Last but not least: Time-base module will be retested right before delivery.
Note: The time-base module uses the individual serial number of the OCXO as its own serial number.
Every time-base module has been tested 100% !Please be advised, that this should not be counted as a \"calibration\" by usual means, because the time base had not been adjusted in the individual users unit under specific and known conditions.
Instead a different approach - as a compromise - has been taken, where the time-base module had been mounted inside a Fluke PM6685 counter for a close aproximation to the normal working conditions and (after at least 12 hour warm-up plus up to 12h / 24h measuring time) adjusted to a high accuracy 10 Mhz reference signal.The adjustment process utilized a multi-channel wide bandwidth oscilloscope with parallel tracking on the 10+2 (overflow) digit display of the test-counter PM6685. The 10 Mhz reference signal was supplied by a *very precise*, permanent satellite based GPS-DO frequency standard.
The setting of the adjustment screw of the multi-turn cermet trimmer has been sealed after adjustment. The module is been delivered in a sealed ESD safe bag.Because the units of the PM66xx counter family feature an active power supply for the OCXO even in standby-mode, the time-base module is been permanently powered, which support faster usage and increased stability of the OCXO.Technical Data:
Power supply: provided be the counter\'s own +12VDC or +24VDC power supply, depending on counter type (max. input voltage > 30 VDC)
Frequency: 10.000 MHz(specification => data sheet OCXO)
Crystal oven (OCXO): CTS 1960017 (SC-Cut crystal with proportionaly regulated temperature control)
Production date OCXO: starting 2006
Signal type: Sine wave like (termination: 51 Ohm)
Current draw (appr.) at +12VDC: 0.35A (appr. 4.5 Watt max) short term (appr. 4 min) during warm-up, after that 0.12A (appr.. 1.4 Watt max) permanently at constant temperature
Dimensions (LxWxH): 76 x 43 x 21 mm
Manufactured in Germany / English installation instructions included.Note: External links not permitted by !Any questions ? Please contact me.Please make sure before ordering that the time-base module as offered fits your counter in any relevant aspects.The legal stuff:
On offer is only the time-base module, nothing else. Other devices, units, accessories, furniture, deco etc shown in the pictures are not included.
This offer does not cover any further services except the sale of the time-base module.
The module shown is a typical example of what\'s been delivered.
All items delivered have been extensively tested during the manufacturing process, as stated, and again immediately before shipment.
All data shown are either excerpts from the manufacturers data sheets or stated to the best of the seller\'s knowledge.
The seller provides this unit on a non-commercial basis, it\'s a private sale. Returns will not be accepted. All sales are final.
The sales-prize does not cover any duty, customs or delivery fees, provisions, commissions etc. if exporting/importing the item. These have to be paid solely by the buyer.
Any risks or damages during transportation due to the delivery of these items offered, if not stated otherwise, are not covered by the seller and have to be handled by the buyer himself.
These statements will not limit the buyers statutory rights.Delivery:
Economy Int\'l.: \"Large\" letter-type package (cardboard boxed) with \"Priority\" handling, confirmation of delivery but no insurance.
Other delivery options like insurance are available upon request: Please contact me beforehand.
Note: Shipment across borders normally will take longer than usual, especially outside the EU.Fluke Philips Counter PM6674 PM6680 PM6681 PM6685 PM9679 PM9690 PM9691 PM 6674 6680 6685 6681 Time-base Crystal oven OCXO XO TCXO
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