FEI frequency electronics-rfs_12pg 电路图.pdf

FEI Communications, Inc. A Subsidiary of Frequency Electronics,Inc. 55 Charles Lindbergh Blvd., Mitchel Field, NY 11553 TEL: 516-794-4500 FAX: 516-794-4340 Visit us at: RUBIDIUM ATOMIC F R E Q U E N C Y S T A N D A R D S Low Cost Atomic Standards.The Perfect Replacement for Precision Quartz. Low Phase Noise for Communications and Timing Systems FE-5680A FE-5660A FE-5652A FE-5650A RadioFans.CN 收音机爱 好者资料库 FE-5650A FE-5660A STANDARD OUTPUT FREQUENCY IS 5 OR 10 MHz SHORT TERM:ALLAN DEVIATION 3x10-11/ t LONG TERM: AGING 5x10-11/MONTH TEMPERATURE: 3x10-10, -5 TO+50C FE-5652A EXTREMELY SMALL: 3x3x1.4 IN. DIGITALLY PROGRAMMABLE TO 1x10 -13 FREQUENCY: 1 Hz TO 20 MHz this causes the light reaching the photocell to decrease. The decrease in light, when the microwave frequency is equal to the sharply defined Rubidium frequency, is then converted electronically to an error signal with phase and amplitude information that is used to steer the VCXO via its control voltage and keep it on frequency at 50.255+ MHz. Output frequencies for Options 02 are provided by the Digital Programmable Synthesizer. Option 02 is an RS-232 remote digitally controlled output with a frequency range of 2 x 10-7at a resolution of 5 x 10-12. Figure 2 4 OPTIONS OPTION NO.FREQUENCY STABILITY 284x10-12/day, 5x10-10/year 292x10-11/year after 1 year (4x10-11/month) 31Allan Dev = 5x10-12/ t 32f vs. T= 1x10-10 48f vs. T= 5x10-11 OPTIONOUTPUT CHARACTERISTICS 02RS232 control* 09Square Wave 12Analog Tuning 16-80 dBc Spurious for 5 MHz 211.0 VrmsOutput 26LOCK=TTL High 30Analog Tuning: 0 to 10v 357E-9C-Fld Adj *Consult factory OPTIONINPUT VOLTAGE OPTIONS 2015 VDC 2522 VDC to 32 VDC 3415 & 5 VDC Input (FE-5660) 46Reverse Voltage Protection OPTIONOTHER 18Conformally Coated 22MIL environment (foamed) 46Reverse Voltage Protection OPTION NO.OUTPUT FREQUENCY *0150.255055 MHz Sine Wave 035 MHz 0415 MHz 0513 MHz 062.048 MHz 0710.23 MHz *08Customer Frequency *Nominal Frequency 5x10-8 *1 Hz to 10 MHz sq. wave, TTL Comp., 5 MHz to 20 MHz sine wave. OPTIONTEMPERATURE RANGE 36-44Consult Factory (from -55c to +85c) 5 Rubidium atomic frequency standards are being used increasingly in telecommunication applications, particularly wireless telephone networks. The possibility of frequency stability sufficient to eliminate the need for sched- uled re-calibrations, along with small size, low power require- ments, wide temperature range operation, and low cost, make these devices attractive candidates for telecommunication applications. In this paper, two new Rb frequency standard designs the FE5680A and FE5652A have been optimized for such appli- cations. The first design is a low profile device, in a package less than 1 inch in height. This device is designed to operate over the temperature range -10 to +60C, with less than 1E-10 frequency error. The second design is a wide temperature range device, which operates from -40 to +85C, with less than 1E-10 frequen- cy error. This unit employs a thermo-electric cooler to maintain the Rb absorption elements at acceptable temperatures at the high end of the ambient temperature range. These devices are presently in production. Performance results of production devices are presented. Introduction The FE-5680ARb frequency standard is 3.5 x 5 x 1 inches, a design suited to PC board slot mounted applications. This product is shown in Figure 1. A simplified functional block diagram is shown below. (Figure 3) The FE-5652ARb frequency standard is 4.7 x 6 x 3 inches. This larger package allows space for a thermo-electric cooler for the physics package, as well as circuitry to lock the output fre- quency to a 1 PPS reference signal as provided by GPS receivers. This product is shown in Figure 3. A simplified block diagram is shown below. Many commercial applications for precision frequency standards demand performance over an extended tem- perature range. Often frequency variation with temperature is the performance-limiting feature of these devices for CDMA holdover applications. The two products described in this paper have both been designed to operate over extended temperature ranges while guaranteeing a frequency variation of less than 1E-10. The FE-5680A operates at any temperature between -10 and +60C, a temperature range required for indoor rack- mounted telecommunication hardware with limited air flow. The FE-5652A operates at any temperature between -40 and +85C, a temperature range required for outdoor, limited access, low maintenance telecommunication hardware. General Performance Characteristics Performance characteristics for these Rb frequency standards are shown in electrical characteristics and options. It is immediately apparent the performance of the two designs is very similar. The only differences are that the FE-5652A requires a 28 VDC (nominal) input, and whereas the FE-5680A requires a 15 VDC (nominal) input. The power dissipation of the FE-5652A is 16 watts, as opposed to the 11 watts dissipated by the FE-5680A. The extra power required for the FE-5652A is needed for the thermo-electric circuit and the external reference lock circuitry. Frequency vs. Temperature As mentioned above, frequency variations due to ambi- ent temperature variations can easily swamp other sources of instability for a Rb frequency standard operating in a real life environment. Therefore special attention was given to frequency stability vs. temperature in these designs. Figures 5 and 6 show typical performance data for FE-5680A and FE-5652A Rb stan- dards over the ambient temperature range. In addition to the information provided by these plots, it is useful to understand the distribution of performance associated with a production lot of these devices. Table 2 provides this information. APPLICATIONS Figure 3 Figure 4 Block Diagram, FE-5652A 6 Table 2 Frequency vs. Temperature Statistics, FE-5680A Lot IDNo. of UnitsMean fStd. Dev. (E-10)(E-10) 43340.000.304 4436-0.090.416 The information in this table shows that the mean total frequency deviation over temperature is very small. What this really means is that the frequency deviation is equally likely to be positive or negative. The standard deviation values give an indication of the range of deviations to be expected amongst production devices. Frequency Stability Allan deviation stability data for the FE5680A and FE5652A Rb standards are shown in Figure 7. The measurements used to derive the Allan deviation were all made at 25C. It is of interest to note that the result for SN 4005 is significantly improved by comparing it to another Rb standard (SN 5339) rather than a Cs reference. This indicates that the result is limited by the stability of the Cs reference. Figure 7 Allan Variance for several units Summary Performance results for two new Rubidium frequency standard products have been reported. These products continue the trend toward small, robust, high-performance atomic frequency standards capable of operating in harsh non-laboratory environ- ments, yet providing stabilities approaching those measured under controlled laboratory conditions. These devices are well suited to the demands of the telecommunications industry for increasingly precise time and frequency references capable of operating un-attended in harsh environments. APPLICATIONS 7 TIME/FREQUENCY ERROR CONVERSION CHART 8 FOR CONSTANT FREQUENCY OFFSET TIME/FREQUENCY ERROR CONVERSION CHART 9 FOR LINER FREQUENCY DRIFT 5650A 5652A 10 TABLE 1 PINFUNCTION 1+15V 2+15V RTN 3LOCK INDICATOR (BIT) 4+5V 5+5V RTN 6NC 7FINE TUNE RTN 8FINE TUNE 9NC PART NUMBER OF THIS DEVICE IS CONTROLLED BY CCD B115010-13480 5680A 5660A 11 OTHER FEI PRODUCTS FE-102A - CRYSTAL OSCILLATOR OPERATION 100 MHz WITH LOW PHASE NOISE: -172 dBc FE-101A - CRYSTAL OSCILLATOR SUBMINIATURE OVEN CONTROLLED DESIGN, ONLY 1.27X1.33X1.33 WITH FAST WARM UP LESS THAN 2 MINUTES FE-103A- CRYSTAL OSCILLATOR DOUBLE OVEN DESIGN WITH EXCELLENT STABILITY: 1X10-11/SEC FE-7923A- DISTRIBUTION AMPLIFIER AN ECONOMICAL, 10-CHANNEL SINEWAVE DISTRIBUTION AMPLIFIER OPERATING FROM 1 MHz THROUGH 10 MHz FEI Communications, Inc. A Subsidiary of Frequency Electronics,Inc. 55 Charles Lindbergh Blvd., Mitchel Field, NY 11553 TEL: 516-794-4500 FAX: 516-794-4340 Visit us at: Specifications Subject to Changes Printed USA 2M699