FEI 5680 TECH MANUAL 电路图.pdf

TECHNICAL MANUAL TM0110-2 RUBIDIUM FREQUENCY STANDARD MODEL FE-5680A SERIES OPTION 2 OPERATION AND MAINTENANCE INSTRUCTIONS RadioFans.CN 收音机爱 好者资料库 Rubidium Frequency Standard Model FE-5680A with Option 2 Frequency Electronics, Inc. Sheet 1 TM0110-2 NOV 2000 RadioFans.CN 收音机爱 好者资料库 TABLE OF CONTENTS Section 1- 1-1 1-1.1 1-1.2 1-1.3 1-1.4 1-2 1-2.1 1-2.2 1-2.3 1-2.4 1-2.5 Section 2- 2-1 2-1.1 2-1.2 2-2 2-3 Section 3- 3-1 1 2 1 2A 2B 3 4 5 Technical Description Equipment Description General Controls Packaging/Connectors Reference Data Functional Description Frequency Lock Loop Voltage Regulator Rubidium Physics Packager Operation VCXO Operation Output Frequency Synthesis Operation and Use Installation Site Selection Cabling Data Turn-On Procedure Frequency Adjustment Repairs General Rubidium Frequency Standard, Outline Drawing Rubidium Frequency Standard, Block Diagram Rubidium Frequency Standard FE-5680A Series Option Summary Connector Functions (except Option 25) Connector Functions: Option 25 Reference Data Cabling Data Byte Ordering of Serial Message 3 3 3 4 4 10 10 10 10 11 11 13 13 13 14 15 18 5 6 7 8 8 9 13 16 Frequency Electronics, Inc. Sheet 2 TM0110-2 NOV 2000 LIST OF ILLUSTRATIONS LIST OF TABLES RadioFans.CN 收音机爱 好者资料库 Section 1. TECHNICAL DESCRIPTION EQUIPMENT DESCRIPTION 1-1 General 1-1.1 The Rubidium Frequency Standard (RFS) FE-5680A Series consists of self-contained, solidstate, modular,atomic frequency standards available in various options, depending on the output frequency, package, and supply voltage requirements. The entire series may be grouped into several versions according to the output interface, which can be adapted to different requirements. The simplest version provides a sine wave output at 50.255+MHz (FE-5680A Option 01). Another version uses a factory-set direct digital synthesizer (DDS) in the output interface allowing virtually any user specified output frequency from 1 Hz to 20 MHz for square wave and sine wave. The standard sinusoidal frequency generated by the RFS is 10 MHz. The following standard frequencies are also available: 2.048,5,10.23,13 and 15 MHz. A third version incorporates a digital communication link in addition to the DDS output (FE-5680A Option 02). The enables remote adjustment of the output frequency by com- puter through an RS-232 interface. Refer to Table 1 for a summary of the FE-5680A Series by option. Different options may be combined to form customized configuration based on output frequency, packaging and supply voltage requirements. Controls 1-1.2 There is one external frequency adjustment control on the RFS. With the external fre- quency adjust potentiometer, the setting resolution is 1 x 10-11 over a range of 3 x 10-9. Frequency Electronics, Inc. Sheet 3 TM0110-2 NOV 2000 Packaging/Connectors 1-1.3 The standard RFS package is illustrated in Figure 1, and measures .98 x 3.47 x 4.92 inches. Input power is supplied through a 9-pin D-subminiature connector. The RF output is sup- plied on an SMA coax connector. Input/Output functions for the RFS are defined in Table 2. Reference Data 1-1.4 Reference data applicable to the RFS are listed in Table 3. The data include output signal characteristics, environmental requirements and input requirements. Frequency Electronics, Inc. Sheet 4 TM0110-2 NOV 2000 Frequency Electronics, Inc. Sheet 5 FIGURE 1. RUBIDIUM STANDARD OUTLINE MODEL FE-5680A TM0110-2 NOV 2000 5.44 4.92 3.99 1.81 J1 CONNECTOR 9 PIN J2 SMA .46 3.47 .31 .44 .98 1.24 2.49 3.73 .13 1.04 2.07 3.11 4.15 5.18 .125 1.06 .13 FREQUENCY ELECTRONICS, INC. 55 CHARLES LINDBERGH BLVD. MITCHEL FIELD, NY 11553 RUBIDIUM FREQUENCY STANDARD PN, FE-5680A OPTION, Frequency Electronics, Inc. Sheet 6 FIGURE 2. RUBIDIUM FREQUENCY STANDARD BLOCK DIAGRAM MODEL FE-5680A TM0110-2 NOV 2000 01 50.255055 MHz Sine Wave 02 Remote Digital Control - RS-232; Resolution: 1.8 x 10-7Hz 03 5 MHz-FEI Standard Frequency 04 15 MHz-FEI Standard Frequency 05 13 MHz-FEI Standard Frequency 06 2.048 MHz-FEI Standard Frequency 07 10.23 MHz-FEI Standard Frequency 08 Customer Specified Frequency 1 Hz to 20 MHz. 09 Square Wave Output : TTL 16 mproved Spurious: -80 dBc at 5 MHz from carrier. 18 Conformally - coated PC Boards 21 Increased RF output level of 1.0 Vrms (+13 dBm). 22 Unit is foamed for operation in severe shock and vibration environment. 25 Operates on a single +22 to 32 Vdc supply voltage instead of +15. 26 Loop Lock Indicator reversed 3Vdc=Locked 28 Improved Drift Stability:4 x 10-12/day and 5 x 10-10/year 29 Improved Drift Stability:2 x 10-10/year after 1 year 30 Analog Tuning: 0 to 10V 31 Short Term Stability: 5 x 10-12 32 Frequency vs. Temperature : 1 x10-10 35 Analog Tuning: 7 x 10-9 range 36-44 Extended temperature ranges from -55 to +71 45 Drift Stability: 1 x 10-11/month. 46 Reverse Voltage Protection. 48 Frequency vs. Temperature :5 x 10-11. 50 Special Configuration # 1 55 Special Marking 57 Special Configuration # 2 TABLE 1. RUBIDIUM FREQUENCY STANDARD FE-5680A OPTION SUMMARY OPTION DESCRIPTION Frequency Electronics, Inc. Sheet 7 TM0110-2 NOV 2000 PIN FUNCTION NOTES J1-1 +15V DC power input J1-2 +15V Return Provides DC return J1-3 Loop Lock Indicator Indicates whether or not the output frequency is stabilized to the Rb atomic reference J1-4 NOT USED J1-5 GROUND Provides DC return, RS-232 return J1-6 NOT USED J1-7 NOT USED J1-8 RS-232 Rx J1-9 RS-232 Tx J2 Frequency Output PIN FUNCTION NOTES J1-1 +22 To 32Vdc DC power input J1-2 +22 To 32V Return Provides DC return J1-3 Loop Lock Indicator Indicates whether or not the output frequency is stabilized to the Rb atomic reference J1-4 NOT USED J1-5 GROUND Provides DC return, RS-232 return J1-6 NOT USED J1-7 NOT USED J1-8 RS-232 Rx J1-9 RS-232 Tx J2 Frequency Output TABLE 2A. CONNECTOR FUNCTIONS (EXCEPT OPTIONS 25) TABLE 2B. CONNECTOR FUNCTIONS:OPTION 25 Frequency Electronics, Inc. Sheet 8 TM0110-2 NOV 2000 PARAMETER SPECIFICATION Frequency 10 MHz* Type Sinusoidal Amplitude (minimum) 0.5 Vrms into 50(+7dBm) Adjustment Resolution 3Vdc=Unlocked < 1Vdc=Locked Input Power (25) 11 watts steady state, 27 watts peak DC Input Voltage/Current 15V to 18V 1.8A peak and 0.7A steady-state except Opt 25: +22V to +32V 1.25 peak, 0.5A s-state Ripple +15V: < 0.1Vrms Warm-up Time < 5 minutes to lock 25 Size 25 x 88 x 125 mm .98 x 3.47 x 4.92 inches Weight 434 grams 15.3 oz. TABLE3. REFERENCE DATA for RUBIDIUM FREQUENCY STANDARD FE-5680A *May be factory set at any frequency from 1Hz to 20MHz Frequency Electronics, Inc. Sheet 9 TM0110-2 NOV 2000 FUNCTIONAL DESCRIPTION 1-2 Frequency Lock Loop 1-2.1 The RFS uses the property of atomic resonance in a Rubidium Physics Package to con- trol the output frequency of a 50.255 x MHz Voltage Controlled Crystal Oscillator (VCXO) with a Frequency Lock Loop (FLL). The FLL functional blocks consist of the RF Generator, Lock-in Amplifier, and the Rubidium Physics Package. Figure 2 provides a functional block diagram of the RFS. Frequency locking of the VCXO is accomplished by operating the Rubidium Physics Package as a frequency discriminator, i.e., departures of a frequency derived from an input signal (50.255xMHz from the VCXO) from a defined center fre- quency (Rubidium atomic resonance) produce a dc output signal (control voltage). This dc output signal has a magnitude and polarity directly related to the magnitude and direc- tion of deviaton from the defined Rb center frequency. Once the FLL has been established, the system generates a loop-locked indication which can be monitored on pin 3 of the J1 connector. Depending on the option selected, the 50.255x MHz VCXO output is used as the clock input for direct digital synthesis within the Synthesizer or the Digitally Program- mable Synthesizer, or the Buffer Amplifier. Voltage Regulator 1-2.2 The RFS is powered by the Linear Regulator which requires a +15 Vdc input voltage. Input current requirements are 1.8A peak and 700 mA steady state for the +15V input. Option 25 is powered by a Switching Regulator which accepts a single +22 to +32 Vdc input voltage and supplies +15V to the RFS. The peak input current requirement is 1.25A: steady state operating current is 500 mA. Rubidium Physics Package Operation 1-2.3 The Rubidium Physics Package incorporates a rubidium cell, rubidium lamp, and servo electronics to utilize the ground-state hyperfine transition of the rubidium atom, at approxi- mately 6.834x GHz.The VCXO is locked to the rubidium atomic resonance in the following manner. The VCXO frequency of 50.255x MHz is an exact sub-multiple ( 36) of the atomic resonance frequency at 6.834x GHz. A microwave signal, having a frequency in the vicinity of 6.834x GHz, is generated from the nominal 50.255x MHz VCXO input. This microwave signal is used to resonate vaporized rubidium atoms within a sealed glass Rb resonance cell that is placed in a low Q microwave cavity. Frequency Electronics, Inc. Sheet 10 TM0110-2 NOV 2000 The microwave frequency generation method is designed so that the VCXO frequency is exactly 50.255x MHz when the microwave frequency is exactly equal to 6.834x GHz. The frequency of the signal applied to the microwave cavity can be maintained equal to 6.834x GHz by generating an error signal when the frequency varies, and using this error signal to servo the VCXO via its control voltage. The error signal is generated in the physics package. Light from the rubidium lamp, pro- duced by an excited plasma discharge, is filtered and passed through the rubidium reso- nance cell where it interacts with rubidium atoms in the vapor. After passing through the resonance cell, this light is incident upon a photocell. When the applied microwave fre- quency is equal to 6.834x GHz, the rubidium atoms are resonated by the microwave field in the cavity; 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 50.255x MHz. VCXO Operation 1-2.4 The VCXO operates nominally at 50.255x MHz. The VCXO has two isolated outputs; one output is provided to the Rubidium Physics Package for comparison purposes, and the other output is provided to either the Synthesizer or Remote Programmable Synthesizer, or to the Buffer Amplifier (for option 1). Output Frequency Synthesis 1-2.5 Option 1 uses a Buffer Amplifier to provide a 50.255055 MHz non-programmable sinewave output. This version is for systems that have their own synthesis capabilities. For options 03 through 07, standard output frequencies of 2.048, 5, 10.23, 13 and 15 MHz are provided by the Direct Digital Synthesizer (DDS) within the Synthesizer. Correspond- ing standard output frequencies and options are as follows: Option Standard Frequency (MHz) 03 5 04 15 05 13 06 2.048 07 10.23 Frequency Electronics, Inc. Sheet 11 TM0110-2 NOV 2000 Option 08 is reserved for customer specified output frequencies between 1Hz and 20 MHz. Option 09 produces a TTL wave output between 1 Hz and 20 MHz at a duty cycle of 50%. Option 02 output is RS-232 remote-controllable with a resolution of 10 years for the EEPROM memory. Input Command: Data: aa bb cc dd Data Length: Command Length: Remarks: Range: 2C 09 00 25 aa bb cc dd 32 bit signed integer where aa is the most significant byte and dd is the least significant byte of the32 bit signed integer. 4 bytes 9 bytes This command sets the frequency offset. Value represents a 32 bit signed integer. 7F FF FF FF = 2,147,483,647= +383 Hz 80 00 00 00 = -2,147,483,647= -383 Hz Frequency Electronics, Inc. Sheet 16 TM0110-2 NOV 2000 2-3.3.2 Set Frequency Offset, Dont Save to EEPROM 2Eh This command is used to perform a frequency adjustment which will not be “remember- ed” by the FE-5680A. If the FE-5680A is turned off after type of frequency adjustment, it will return to the pre-adjusted frequency setting after being powered on at a later time. Typically this command is used for locking the FE-5680A to a more stable reference. There is no limit on how often this command can be sent to the FE-5680A. 2-3.3.3 Request Frequency Offset 2Dh Input Command: Data: aa bb cc dd Data Length: Command Length: Remarks: Range: 2E 09 00 27 aa bb cc dd 32 bit signed integer where aa is the most significant byte and dd is the least significant byte of the 32 bit signed integer. 4 bytes 9 bytes This command sets the frequency offset. Value represents a 32bit signed Integer 7F FF FF FF = 2,147,483,647= +383 Hz 80 00 00 00 = -2,147,483,647= -383 Hz Frequency Electronics, Inc. Sheet 17 Input Command: Command Length: Response: Data: aa bb cc dd Data Length: Response Length: Remarks: 2D 04 00 29 4 bytes 2D 09 00 24 aa bb cc dd 32 bit signed integer where aa is the most significant byte and dd is the least significant byte of the 32 bit signed integer. 4 bytes 9 bytes This command reads the Frequency Offset value. Value represents a 32 bit signed integer. TM0110-2 NOV 2000 Section 3. REPAIRS GENERAL 3-1 The Rubidium Frequency Standard (RFS) is not field repairable. All units that need repair should be shipped to the address given below. Prior to returning any units, contact the Marketing Department at extension 5030 to obtain an RMA number. Frequency Electronics, Inc. Sheet 18 TM0110-2 NOV 2000