The RF Telecommunications System for the New Horizons Mission to Pluto1,2 Christopher C. DeBoy, Christopher B. Haskins, Thomas A. Brown, Ronald C. Schulze, Mark A. Bernacik, J. Robert Jensen, Wesley Millard, Dennis Duven, Stuart Hill The Johns Hopkins University ~ Applied Physics Laboratory 11100 Johns Hopkins Road Laurel MD 20723 chris.deboy@jhuapl.edu 1. INTRODUCTION Abstract—This paper describes the design and development of the RF telecommunications system for the New Horizons mission, NASA’s planned mission to Pluto. The system includes an advanced, low-power digital receiver, and a card-based transceiver implemented within an integrated electronics module. An ultrastable oscillator (USO) provides the precision frequency reference necessary for the uplink radio science experiment. The 2.1 meter high gain antenna is the primary communications antenna, with medium gain and low gain antennas used for wider beamwidths during early operations, cruise-phase and sun-pointing mission phases. Mission Description New Horizons is NASA’s planned mission to Pluto, with a projected launch date in January of 2006. The fly-by mission seeks to characterize the geology and atmosphere of Pluto and its large moon Charon. At launch, the spacecraft follows a heliocentric trajectory to a Jupiter fly-by for gravity assist in 2007, and then settling into a long 8-year cruise to the outermost planet. The baseline encounter date for the Pluto fly-by is July, 2015. An extended mission for the spacecraft would see fly-by’s of one or more Kuiper Belt objects, the set of small planetoids of the outer solar system of which Pluto is considered the largest member. Mission trajectories are shown in Figure 1 below, with the three different arrival dates corresponding to launches at different times in the launch window. The paper will discuss the salient aspects of the system design, including design drivers from mission operations, science, and spacecraft considerations. It will also detail individual subsystems’ performance, operational modes (including beacon mode operation), and navigation technology, including the first deep-space flight implementation of regenerative ranging. Pluto EncounterJupiterNeptuneUranusSaturnPlanetary position at Pluto encounterin July 2015Onward to Kuiper Belt Object(s)JupiterNeptuneUranusSaturnPlanetary position at Pluto encounterin July 2015JupiterNeptuneUranusSaturnPlanetary position at Pluto encounterin July 2015Onward to Kuiper Belt Object(s)Jupiter Gravity Assist FlybyFeb -Mar 2007Jupiter Gravity Assist FlybyFeb -Mar 2007LaunchJan 11 –Feb 2, 2006 LaunchJan 11 –Feb 2, 2006 July 2015July 2015July 2016July 2016July 2017July 2017 TABLE OF CONTENTS 1. INTRODUCTION.......................................1 2. OVERALL SYSTEM..................................2 3. UPLINK CARD.........................................4 4. DOWNLINK EXCITER CARD....................6 5. ULTRASTABLE OSCILLATOR..................7 6. ANTENNA SUBSYSTEM............................9 Figure 1 Planned Mission Trajectory 7. NAVIGATION SUPPORT.........................11 8. REGENERATIVE RANGING....................12 Pluto is on average 39 AU from the Sun, but due to its highly eccentric orbit will be approximately 32 AU from the Earth at encounter (1 AU = approximately 150 million km.) At that range, the round trip light time to the spacecraft is over 8 hours. Science observations commence in the months 9. SUMMARY.............................................14 REFERENCES.............................................14 BIOGRAPHIES............................................15 1 0-7803-8155-6/04/$17.00©2004 IEEE 2 IEEEAC paper #1369, Version 4, Updated December 22, 2003 1
preceding encounter, with the most intense instrument activity during the several hours before and after closest approach. The scope of the scientific effort includes ultraviolet, visible, and infrared imaging and spectroscopy, particle detection, and radio science. The mission is led by Principal Investigator Dr. Alan Stern at Southwest Research, Inc, and the spacecraft project is led at the Johns Hopkins University Applied Physics Laboratory. Telecommunications Requirements The high level requirements on the RF telecommunications system are to provide uplink and downlink capability throughout the primary and extended mission, to support radiometric range and Doppler tracking for precise navigation, and to incorporate an uplink radio science capability. A minimum post-encounter end-of-playback data rate requirement of 600 bps drives the high gain antenna (HGA) and TWTA designs. The ability to command through the medium gain antenna (MGA) out to 50AU for the extended mission sets the MGA receive gain. 2. OVERALL SYSTEM Overview A block diagram of the New Horizons RF Telecommunications System is shown in Figure 3. Integrated Electronics Module (IEM)—Two IEMs are used onboard to house many spacecraft functions, including the command and data handling system, the instrument interface circuitry, the telemetry interface function, the solid state recorder, and the receiver and exciter sections of the telecommunications system, along with the DC-DC converters that power them all. This implementation reduces the overall harness requirement and results in mass and cost savings while offering a flexible platform for future development. Figure 2 The New Horizons Spacecraft Sets of Uplink, Downlink, and Radiometrics cards are contained within each of two integrated electronics modules (IEMs). The Uplink Card (described in detail in Section 3) provides the command reception capability, as well as a fixed downconversion mode for the uplink radioscience AftLGARHCSwitch AssemblySP3TLNALNADiplexerLHCRHCFilterMGA0.3m dishS4DiplexerFilter12W TWTAHGA2.1m DishUSO BLHCS3LHCRHCRHCLHC= Coaxial Cable= Waveguide= Waveguide to Cable Transition12W TWTAHybridCouplerSP3TIEM ADownlinkCardREX / Reg. RangingDigitalReceiverCCDUplink SystemIEM BTo Side AFrom Side AUSO ATo Side BFrom Side BDownlinkCardREX / Reg. RangingDigitalReceiverCCDUplink SystemSPDTSPDTAftLGARHCSwitch AssemblySP3TLNALNADiplexerLHCRHCFilterMGA0.3m dishS4DiplexerFilter12W TWTAHGA2.1m DishUSO BLHCS3LHCRHCRHCLHC= Coaxial Cable= Waveguide= Waveguide to Cable Transition12W TWTAHybridCouplerSP3TIEM ADownlinkCardREX / Reg. RangingDigitalReceiverCCDDigitalReceiverCCDUplink SystemIEM BTo Side AFrom Side AUSO ATo Side BFrom Side BDownlinkCardREX / Reg. RangingDigitalReceiverCCDDigitalReceiverCCDUplink SystemSPDTSPDTSPDTFigure 3 RF Telecommunications System Block Diagram 2
experiment (REX). Since at least one Uplink Card must be powered at all times, this digital receiver’s very low power consumption (2.5W secondary) has been an enabling technology for the mission. The Downlink Card (Section 4) is the exciter for the Traveling Wave Tube Amplifiers (TWTAs), and encodes block frame data from the spacecraft Command and Data Handling (C&DH) system into rate 1/6, CCSDS Turbo-coded blocks. It also calculates and inserts navigation counts into the frame data to support the noncoherent Doppler tracking capability, and is used to transmit beacon tones during cruise periods. The Radiometrics Card contains the REX and Regenerative Ranging Functions. Ultrastable Oscillators—Two USOs (see Section 5) provide the ultimate frequency reference for the Uplink and Downlink Card local oscillators and clocks. The USOs are cross-strapped with a transfer switch and power splitter to retain redundancy in the Uplink and Downlink Cards in the event of a USO failure. Hybrid Coupler—A hybrid coupler is connected to the Downlink Exciter outputs and TWTA RF inputs. This enables either exciter to work with either TWTA. In addition to the increased reliability, this gives the Mission Operations team flexibility during downlink events, in that the downlink polarization sense (RHC or LHC) can be changed by powering the appropriate TWTA without having to change IEMs to use the other exciter. It also enables the tantalizing prospect of nearly doubling the post-encounter downlink data rate. If both TWTAs can be powered at once (a spacecraft power and thermal margin issue that will be settled during cruise), then, using one exciter, a dual-polarized downlink signal (LHC and RHC) can be transmitted. The Deep Space Network (DSN) has recently tested their single-antenna polarization combining capability and achieved the expected > 2.5 dB processing gain. Should this mode prove operable, it would provide a > 44% reduction in the post-encounter playback duration and significant cost savings. RF Switching and Routing—The RF switch assembly interconnects the antenna suite with the redundant TWTAs and the rest of the communications system. A waveguide diplexer from Ciao Wireless provides the necessary isolation between receive and transmit paths. A bandpass filter prior to the LNA yields more rejection of the downlink signal in the receive path to keep the wideband LNA far from saturation. A SP3T waveguide switch connected to the antenna port of the diplexer enables the RF signals to flow to or from the HGA, MGA, or LGAs. (For the LGAs, an additional SMA transfer switch is used to select the aft or forward antenna.) All connections to the HGA are waveguide to minimize loss, whereas SMA coaxial cables are used for ease of assembly and routing for the MGA and LGA runs. TWTAs—Two 12W X-Band TWTAs manufactured by Thales, Inc., provide the high power RF downlink output The selected power level is a compromised between data rate and beamwidth performance and power dissipation in this power-limited spacecraft. Antennas—Three antennas are mounted to the forward side of the spacecraft and centered on the spin axis. Spin axis mounting was desirable from both mechanical (greater degree of symmetry about the spin axis) and communications perspectives (high spacecraft spin rates after launch could lead to uplink acquisition and tracking issues if the off-spin-axis distance were too great.) See Section 6 for further discussion on the antenna design. Uplink Radioscience—The RF Telecommunications System incorporates the REX (Radioscience EXperiment) Instrument. REX seeks to characterize the atmosphere of Pluto and (if one exists) of Charon, and to estimate surface temperatures by recording changes in the received uplink signal at various times during encounter. The hardware specific to REX consists of an analog-to-digital converter and the REX Actel FPGA, and is co-located on the Radiometrics Card with the Regenerative Ranging System (Section 8). A wideband IF output from the uplink receiver is fed to the REX circuitry, and the receiver is commanded to a fixed-conversion mode (i.e., carrier tracking is disabled and all LO’s are fixed in frequency.) Any RF input at the appropriate receive frequency is directly downconverted and passed to the REX hardware. Two types of measurements are made. As the spacecraft moves into occultation (the time Pluto blocks the uplink signals from the Earth), samples of the REX filter output are stored to determine the changes in phase and amplitude the uplink signal underwent as it moved through different layers of Pluto’s atmosphere. During occultation, the full bandwidth of the REX IF input is integrated, sampled, and later compared to calibrations to determine the effective antenna noise temperature, which can be used to map the physical temperature of the planet. The REX effort is led by Stanford University, who is responsible for the design of the Actel FPGA. Its inclusion in the RF system mandated tight control of spurious signals in the receiver IF, attention to minimizing the spacecraft system noise temperature (to approximately 200K) and receiver gain variations, and the careful selection of crystal resonators in the USO to achieve the highest level of frequency stability and thus the best performance for REX. 3
3. UPLINK CARD Overview The New Horizons Uplink Card provides X-band carrier tracking, command detection/demodulation, critical command decoding, ranging tone demodulation, a wideband intermediate frequency (WBIF) channel for use by the Radioscience Experiment (REX) and Regenerative Ranging subsystems, and a fixed downconversion mode for REX. This new uplink card design makes use of digital processing techniques to enhance performance and flexibility, while at the same time achieving considerably lower power consumption than predecessor systems. The Uplink Card (Figure 4) is an assembly consisting of three separate printed circuit boards (PCB) mounted to an aluminum heat sink. On one side, a multilayer, polyimide PCB contains the circuitry required for the RF, IF, analog, and digital portions of the X-band carrier tracking receiver, ranging tone demodulation, and the WBIF channel. Attached to this polyimide PCB is an RF downconverter board, which consists of a temperature stable microwave substrate, various microstrip circuits, and the circuitry required to complete the first RF downconversion stage in the uplink card. On the other side, a second multilayer, polyimide PCB contains the required circuitry for the command detector unit (CDU) and the critical command decoder (CCD). Figure 4- Photographs of Uplink Card a) digital receiver side, b) baseband side (CDU and CCD) Design Approach The primary RF carrier tracking, command detection, and turnaround ranging channel performance requirements of the digital receiver system are similar to those of previous deep space RF systems, including both the small deep space transponder (SDST) and CONTOUR RF transceiver systems. Several new design requirements led to a new design approach. These new requirements included reduced power consumption, flexibility in the choice of reference oscillator frequencies, and added support for uplink radioscience (REX) and regenerative ranging. The core receiver design uses a classic double-conversion, superheterodyne approach (Figure 5). The aforementioned RF downconverter board provides several key functions, including power to an external low noise amplifier (LNA) through a microstrip bias tee, band select/image reject filtering, the first downconversion stage, and amplification, tripling, and harmonic filtering of the RF local oscillator (LO). The RF LO is generated at approximately 2474 MHz by a fractional-N synthesizer and routed to the RF downconverter board. The output of the first downconversion stage is the first intermediate frequency (IF), which is approximately 240 MHz. The first IF is bandpass filtered and split into two channels, one narrowband and one wideband. The narrowband channel is used for carrier tracking, automatic gain control, and command demodulation, while the wideband channel is used for turnaround ranging demodulation and generation of the WBIF channel to be used by the REX and regenerative ranging subsystems. Both channels each contain a single-chip receiver integrated circuit (IC), which provides the second downconversion stage, automatic gain control (AGC) amplification, and wideband channel quadrature demodulation. Downconversion to the second IF of 2.500 MHz makes use of an IF LO, which is generated at approximately 242.5 MHz by an integer-N synthesizer. Upon downconversion to the second IF, separate filtering of the wideband and narrowband channels is achieved via discrete filter circuits external to the aforementioned receiver ICs. The 2.5 MHz narrowband IF (NBIF) channel is processed by a 10-bit, 10 Msps analog-to-digital converter (ADC). The resultant sample data is processed by a field programmable gate array (FPGA), which provides a variety of critical receiver functions. The digital receiver FPGA (DPLL) first demodulates the NBIF to baseband. The baseband data is then processed through the digital portions of the carrier tracking loop, power detection, and AGC system. The DPLL’s primary contribution to the carrier tracking loop is in the form of a 20-bit preselect/antialiasing filter and a 64-bit loop filter. The output of the loop filter is used to steer the output frequency and phase of a direct digital synthesizer (DDS), which is in turn used as a carrier tracking reference oscillator in the closed loop carrier tracking system. The DPLL’s primary contribution to the AGC system is in the form of a power detection circuit and filtering used to drive a digital-to-analog converter (DAC), which is in turn used to generate a control voltage that sets the gain in the analog portions of the receiver system. The digital baseband data is also filtered to select the subcarrier, 4
Figure 5 Uplink Card Block Diagram which is then forwarded to the CDU for data demodulation and command detection. For the New Horizons mission, this subcarrier is binary phase shift key (BPSK) modulated with commands at data rates of 2000, 500, 125, and 7.8125 bps. The CDU locks to and tracks the 16 KHz subcarrier and demodulates the command data, passing data and clock over to the CCD. In the CCD, designated critical relay commands are decoded, detected, and immediately sent to the power switching system. The CCD also forwards all commands to the C&DH system. The 2.5 MHz WBIF channel is buffered and routed to the Radiometrics Card for further processing. The 2.5 MHz WBIF is also demodulated in the quadrature demodulator built into the receiver IC. The resultant baseband channel (or ranging channel) is filtered through several filters designed to limit the noise power in this channel as well as reduce the level of various demodulation products, while at the same time allowing the desired ranging tones to pass through with minimal phase and amplitude distortion. The output of this ranging channel is buffered and routed to the downlink card for modulation onto the downlink X-band carrier. In addition, the ranging channel has the capability to route either the demodulated ranging tones or the regenerated pseudonoise (PN) ranging code produced by the regenerative ranging subsystem to the downlink card. 5 Carrier acquisition and tracking is provided via a type-II phase locked loop and noncoherent AGC system. Both the RF and IF synthesized LOs are tuned through the use of a common 30.1 MHz carrier tracking reference clock; this clock is generated by mixing the 30 MHz spacecraft frequency reference with a 100 KHz DDS. The DDS phase and frequency is dynamically tuned by the DPLL carrier tracking system to in-turn tune the RF and IF LOs. An open loop, fixed downconversion mode is required for REX; in this mode, the DDS frequency is set at a fixed value that is reprogrammable during the mission. All clocks and frequency sources in the digital receiver system are referenced to the 30 MHz spacecraft reference oscillator. Features Performance highlights include the following: total secondary power consumption of 2.5 W (including the integrated on-board command detector unit (CDU) and critical command decoder (CCD)), built-in support for regenerative ranging and REX, carrier acquisition threshold of -157 dBm, high RF carrier acquisition and tracking rate capability for near-Earth operations (2800 Hz/s down to -100 dBm, 1800 Hz/s down to -120 dBm, 650 Hz/s down to -130 dBm), ability to digitally tune to any X-band RF channel assignment (preprogrammed on Earth for this mission) without the need for analog tuning and tailoring, use of an even 30.0 MHz ultrastable oscillator (USO) as a frequency reference, a noncoherent AGC system, and best lock frequency (BLF) telemetry accuracy to 0.5 Hz at X-band and BLF settability plus stability error < >
with zero temperature effects (all relative to USO frequency). These results highlight the major performance parameters of the operational and functional RF uplink system. One of the key benefits of moving to a more-digital system is increased operational flexibility. Once in place, successive design iterations in future missions may include in-flight reconfiguration of RF channel assignments, and carrier tracking loop optimization for near-Earth, deep space, and interstellar operational modes. A secondary benefit is the ability to leverage from increasing gate array densities and processing unit speeds, thus contributing to further mass, size, and power savings. Finally, further reduction in hardware assembly steps due to lower parts count and fewer solder connections increases the reliability of these systems. 4. DOWNLINK EXCITER CARD Downlink Card Overview The New Horizons Downlink Card provides an X-band exciter output to be delivered through a hybrid coupler to the spacecraft TWTA for transmission. This output consists of the carrier (either unmodulated or residual) and phase modulation for the telemetry, ranging, or beacon modes of operation. The Downlink Card (see picture in Figure 6 and block diagram in Figure 7) is an assembly consisting of three separate printed circuit boards (PCB) mounted to an aluminum heat sink. On one side, a multilayer polyimide PCB contains the synthesizer and signal conditioning circuitry, along with a temperature-stable microwave substrate containing S- to X-band multipliers and phase modulators. On the reverse side, a second multilayer polyimide PCB contains the digital circuitry for the PCI interface, modulation control, noncoherent Doppler tracking counters, CRC calculation and Turbo encoding functions. Design Approach—Analog Side In this transceiver system, the carrier signal is generated by a PLL synthesizer using the on board 30 MHz USO reference. Two output center frequencies are possible, designated primary and auxiliary. The primary or auxiliary frequency is selected by controlling the divisors in the synthesizer’s parallel load inputs. This capability permits the downlink carrier to be switched between carrier frequencies depending on the state of the uplink carrier lock indicator (allowing the downlink to provide 1 bit of information on the uplink status.) If this coherent simulation mode is disabled the downlink carrier is always at the primary center frequency. The synthesizer output signal at S-Band is mixed with the 30 MHz USO reference to reduce the potential perturbation of the PLL loop by the desired signal and harmonics as it is multiplied to X-band. The carrier is modulated at 4 GHz, with a pair of phase modulators, one for the ranging signal from the uplink card, the other for the telemetry data. The ranging signal is processed by an AGC amplifier stage, which also provides a means of disabling the ranging signal. HBT amplifiers were initially considered for the 4 GHz and 8 GHz RF amplifier stages, but were ultimately changed to GaAs MMIC due to reliability concerns over the extended operational life required for the mission. Figure 6 - Photographs of Downlink Card Left, Analog side, Right Digital side Design Approach—Digital The majority of the Downlink Card’s digital design is contained within a single Actel FPGA, an RTSX72S. Additional circuitry consists of the 5.3 kHz Doppler tracking signal filter, which is implemented in op-amps, and the PROMs and RAMs and interface circuitry. The FPGA design is implemented in VHDL. Its primary function is to Turbo-encode frame data blocks from the C&DH system. The encoder uses the interleaving tables stored in the external, anti-fuse PROMs to create the coded symbol streams, and calculates and inserts a CRC for each frame. The design also includes a PCI interface that enables frame data transfer and downlink bit rate and mode selection. Also included are the noncoherent Doppler tracking counters, including sub-frame count interface and control, CRC calculation and insertion (for each frame), interleaving and turbo encoding, and a subcarrier modulator. Generally for low data rates, this modulator places NRZ line coded symbols onto a 25 kHz subcarrier. Other functional blocks include PN code generators for BER testing, implementation of test modes, and MET (Mission Elapsed Time) counters to accurately record the 6
start time of a frame transmission. (This result is included in telemetry in the next downlinked frame.) A 16 bit control register is used to provide 65532 possible downlink data rates, from a minimum of 6.3578 bps to a maximum of 104.167 kbps. The relation between control word setting n and the data rate is ()1125+=nMHzBitRate (1) where 3 ≤ n ≤ 65536. The fine spacing of data rates about the expected post-encounter playback rate of 1 kbps gives the mission operations team a great deal of flexibility to take advantage of late improvements in the space segment and ground segment system performance. To bound the pre-flight test time required, a subset of these data rates will form the baseline for ground test. Since the CRC must be calculated and inserted before the data interleaving and turbo encoding, it is necessary to pipeline data frames, with the next frame being encoded while the current frame is being transmitted. This requires the use of two RAM frame buffers. In addition, to avoid possible underflow when operating at maximum rates (primarily during test), a third null buffer was included and filled with dummy data should a frame be completely transmitted before the next frame has been encoded. The Downlink Card can also be configured to support Beacon Mode operations. In this mode, a single square wave tone is phase-modulated onto the selected carrier. The frequency of the beacon tone is determined by the setting of the 16bit data rate control register: the tone frequency is the symbol rate that corresponds to the commanded data rate (i.e., the tone frequency is 6x the selected data rate.) This gives the software and mission operations teams flexibility in defining tone frequencies and minimizes the impact of this new capability to the existing card design. The hardware in the DSN supports up to 4 separate defined tone frequencies that can be used. By placing tones on either carrier, 8 different beacon settings can be selected to provide various levels of information. 5. ULTRASTABLE OSCILLATOR Overview The New Horizons Ultrastable Oscillator (USO) is a critical component of the RF telecommunications system and the mission itself. It provides a stable, 30 MHz frequency reference for the Uplink and Downlink Cards’ frequency synthesizers, and the ultimate frequency reference necessary for the uplink radio science experiment. Figure 8 Ultrastable Oscillator Assembly 7
The USO is a sophisticated precision assembly consisting of over 200 electronic components and many mechanical parts (see photo in Figure 6). Its architecture builds on proven heritage designs developed at APL over the last 30 years, and flown recently on such missions as Mars Observer, Cassini, GRACE, and Gravity Probe B. Fundamentally, it is a pristine version of an ovenized crystal oscillator (OCXO). We use carefully selected, 3rd overtone, SC-cut crystal resonators and maintain them at constant temperature to yield excellent frequency stability (short-term to better than 1 part in 1013) and low noise performance. The significant performance improvement over industry grade OCXOs relies on a cylindrical oven design and very uniform heating which results in very small temperature gradients within the crystal resonator blank. A high-gain thermal control loop keeps the crystal resonator temperature stable to within several thousandths of a degree Celsius over the entire operating temperature range of the USO. Crystal resonators for flight will be carefully selected among twenty units for the best aging and short-term frequency stability. 8 Functional Description The block diagram of the USO is shown in Figure 7. The USO consists of six polyimide printed wiring boards populated with military-grade, high-reliability passive and active components: A1 and A2— The A1 board interfaces the electronic circuitry with the resonator, and consists of the oscillator front end, an automatic gain control (AGC) circuit, and a high input impedance buffer amplifier. AGC sets the oscillator start-up loop gain and resonator drive level, which will be carefully tailored for optimum combination of aging performance and short term stability. The A2 board generates the temperature control signal to drive a heater that keeps the oven temperature of the crystal resonator constant. Since both the A1 and A2 boards contain temperature-sensitive circuitry, they are part of the temperature control assembly operating at a fixed temperature. A3 and A4— These boards multiply, filter, and amplify the 5 MHz resonator output to the 30 MHz, +10 dBm signal required in the rest of the RF system. High-Q circuits and multiple transmission zeros in the output stage result in harmonics at levels less than -60dBc and subharmonics at levels of less than -80dBc. A5 and A6— The A5 board collects and conditions the USO telemetry (voltages and temperatures) for output, while the A6 board cleanly regulates the 22V – 35V input bus voltage down to 15V. Performance Highlights The resolution of the New Horizons uplink radioscience experiment depends upon the excellent frequency stability of the USO over the duration of the Earth occultation event at Pluto. Short-term frequency stability (Allan deviation) at 1s and 10 s are specified at 3x10-13 and 2x10-13, respectively, with goals of sub-1x10-13 performance. At this writing, with roughly half of the lot of crystal resonators tested, the best Allan deviation (10 s) achieved is better than 1x10-13.Amp.Amp.X212.25V10VReg.Reg.A4X3Amp.Amp.Amp.A3Osc.AGCAmp.A1EMIfilterDC-DCconverterA615V22V to 35VA5Temperature control assemblyHeaterwireT~85C5MHz10MHz30MHz10dBm30MHz10dBm5MHz3rd O.T.SC-cut10V15V15VOven monitor0.7V to 5V out10V15VA2Temperaturecontrol boardThermistor2V to 15VDC converter monitor3.6V out10V regulator monitor3.6V outHeatertransistorHeatHeat1V to 7VFigure 9 Ultrastable Oscillator Block Diagram
9 A summary of other relevant performance measures is tabulated below. Parameter Specification Output Frequency 30 MHz Output Power (into 50Ω) +10 dBm +/- 1 dB (dual output) Aging Rate