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Subcarrier Extraction System

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Subcarrier Extraction System / / / TRW No 14610-6001-TO-00 / SUBCARRIER EXTRACTION SYSTEM FINAL REPORT December 1969 Prepared for NATIONAL AERONAUTICAL AND SPACE ADMINISTRATION MANNED SPACECRAFT CENTER R&D PROCUREMENT BRANCH HOUSTON TEXAS 77058 0 Under K iContract No NAS9 10229 Ni TI. dun al f PROPRIETARY TO TRWSZYSTEMS GROUP TRW C hd 1i dhdlI d h. dt pupIt hIhfh h 1 1 h dh hp w p I TRW%S, G TRW •51i°TRW ' I 0 E S CE K EDOONDOSBEAC 0 0 g0 " Reproduced by the I for Federal Sctenttf IC & "Technical " lnformfltonl Spr ngtield Va 22151 TRW No 14610-6001-TO-00 N1 18707 SUBCARRIER EXTRACTION SYSTEM FINAL REPORT December 1969 Prepared for NATIONAL AERONAUTICAL AND SPACE ADMINISTRATION MANNED SPACECRAFT CENTER R&D PROCUREMENT BRANCH HOUSTON, TEXAS 77058 Contract NAS9 10229 Thi d un i nt I PROPRIETARY TO TRW SYSTEMS GROUP TRW INC d h II b p d d I d h d i d I d h df yppo lh h h f wh hi I I hdw h h p I w p M ETRWSy m C p TRWI TRW 3Y37EM GROWP ONE SPACE RK RE 0 0 C C L 0 9028 TRW No i4610-600i-T0-00 SUBCARRIER, EXTRACTION SYSTEM FINAL REPORT December 1969 ) - - Approved / / A , R P Tow Jr Section Head RF Section W C Baxter Manager Defense Electronics Department R R Trapp Manager Communications and Defense Electronics Laboratory 11 CONTENTS Page INTRODUCTION i 2 APEX SYSTEM AND UNIT DESCRIPTION 3 ZI System Description 3 Z Z AV APEX Module 5 2 z I Functional Description 5 Z 2 Z Estimate Generation 5 Z2 3 Signal Spectra 6 2 3 APEX Unit I 024-MHz TM Subcarrier 6 Z 4 Biphase Sensing Module 8 Z 5 Delay Line Module t0 2 5 1 Delay Line 10 2 5 2 Delay Line Filter 10 2 6 Buffer Module Description 10 3 APEX CIRCUIT DESCRIPTION I 2 3 1 AV-APEX Module Circuit Description 12 3 1 1 Input Circuitry 1z 3 1 2 Phase Detector 12 3 1 3 Low-Pass Loop Filter and Amplifier 1z 3 1 4 Sweep Circuitry 1z 3 1 5 VCO and VCO Filter 13 3 1 6 AV Data Output 13 3 1 7 CAD 13 3 1 8 CAD Low-Pass Filter and Amplifier 13 3 1 9 Estimation Inhibit and AM Modulator 13 3 1 10 AV Output Driver 14 3 1 i1 Dc Voltage Regulators 14 3 2 TM-APEX Module Circuit Description 14 3 2 1 Input Circuitry 14 3 22 Phase Detector 15 3 2 3 Low-Pass Loop Filter and Amplifier 15 3 2 4 VCO Biphase Modulator and Phase Shift Filter 15 3 2 5 CAD 15 3 Z 6 CAD Low-Pass Filter and Amplifier 15 3 2 7 Amplitude Modulator and Estimate Inhibit Circuitry 16 3 Z 8 AM Output Driver 16 3 Z 9 Biphase Sensor and Pulse Shaper 16 3 Z 10 Demodulator Output and Biphase Modulator Driver 16 3 2 i Dc Regulators 16 11i CONTENTS (Continued) Page 3 3 Biphase Sensing Module Description 17 3 3 1 External Coherent Amplitude Detector and Input Emitter Follower 17 3 3 2 External CAD Input to Signal Output Amplifier 17 3 3 3 Data State Integrator 17 3 3 4 Zero Voltage Threshold Comparators and Biphase Output Drive Circuitry 18 3 3 5 Output Signal Amplifier 18 3 4 Delay Module Description 18 3 4 1 Input-Output Filter Termination 19 3 4 2 Bandwidth 19 3 5 Buffer Module Description 19 3 5 1 Input Amplifier 19 3 5 2 Estimate Summation and Error Distribution Network 19 3 5 3 Output Amplifier 20 3 5 4 DC Bias Transfer Network 20 4 APEX SYSTEM ANALYSIS 21 4 1 AV -APEX Unit Analysis 21 4 2 TM - APEX Unit Analysis 25 5 APEX SYSTEM SCHEMATICS AND LAYOUTS 30 6 CONCEPTUAL REVISIONS 37 6 1 Revised Apollo Apex System 37 6 2 Revised System Description 38 6 2 1 AV APEX Unit Description 40 6 2 2 TM APEX Unit Description 42 6 2 3 TV APEX Unit Description 43 7 SIGNAL SIMULATION EQUIPMENT 46 8 POWER SUPPLIES 49 9 TEST RESULTS 53 t0 HARDWARE 57 i1 NEW TECHNOLOGY/INVENTIONS 61 iv ILLUSTRATIONS Page 2 1 APEX Block Diagram 4 Z-2 AV Module Block Diagram 5 Z 3 Video Spectra - Near 1 25 MHz 6 2-4 TM Module Block Diagram 7 2-5 Biphase Sensing Module Block Diagram 9 2-6 Delay Line Filter Module Block Diagram 10 2-7 Buffer Module Block Diagram ii 3 1 AV Unit Top of Chassis View 12 3-2 TM Unit Top of Chassis View 14 3-3 Biphase Sensing Unit Top 17 3-4 Delay Line Module Top 18 3-5 Buffer Unit Top of Chassis Viev 19 4-I AV Power Spectrum 22 4-2 Suppression Versus Frequency Z3 4-3 TM Signal Spectrum 25 4-4 Phase Tracking Loop 26 4-5 Error Rate Versus S/N 27 4-6 TM Phase Transition Sensing Circuit 27 4-7 Signal Spectrum at Integrator Input (Neglecting Double Frequency Terms) 28 5-1 APEX Modules Interconnection Diagram 31 5-2 AV Module Schematic 32 5-3 TM Module Schematic 33 5-4 Biphase Sensing Module Schematic Diagram 34 5-5 Delay Line Filter Schematic Diagram 35 v ILLUSTRATIONS (Continued) Page 5-6 Buffer Module Schematic 36 6-i Revised TV-APEX System 39 6-Z AV APEX Unit 41 6-3 TM APEX Unit 42 6-4 TV APEX Unit 43 6-5 TV Estimator Filter Block Diagram 44 7-i Signal Simulator Block Diagram 47 7-2 Subcarrier Simulator 47 8-1 Subcarrier Extraction Unit Front View 49 8-2 Cabinet Rear-View Drawer and Dual Power Supply 50 8-3 Strapping Pattern - Rear Panel Control H/P 6101A Power Supplies 51 8-4 Panel - Dual Power Supply (Rear Mount) 52 9-i NASA Photograph S-69-57736 54 9-2 NASA Photograph S-69-57738 55 9-3 NASA Photograph S-69-57737 56 10-i Front Panel 58 10-2 Cabinet Angle View Showing Modules and P/S 59 10-3 Front Quarter View of Drawer with Modules 59 10-4 Inside Drawer Front Panel Detail 60 10-5 Drawer Inside Back 60 Vl. i INTRODUCTION This final report was prepared by TRW Systems Group for the National Aeronautical and Space Administration Manned Spacecraft Center under Contract No NAS9-10229 The contract objective was to design fabricate test and deliver in a minimum amount of time a Subcarrier Extraction System capable of removing two high-level subcarriers from a TV baseband spectrum This removal process was to hold disturbance of the TV spectrurnto aminimum The two offending subcarriers are at i 0Z4 MHz and i 25 MHz The 1 024-M-z subcarrier is a biphase signal modulated at either a i 6-kbit or a 51 6-kbit rate (TM) The I Z5-MHz subcarrier is an FM-FM signal modulated by baseband signals consisting of analog bio-med information and voice (AV) The relative levels between the TV baseband spectrum and the two subcarriers is determined by the relative FM deviation magnitudes of the Z-GHz carrier frequency and are understood to be TV - AF 1 50 MHz TM- AF 0 45 0 60 MHz AV - AF 0 Z25 MHz The overall signal-to-noise (S/N) ratio at lunar distances accord­ ing to the information provided by NASA is S/N = 5 3 dB/5 3 MIVlz-noise bandwidth for the 85-ft steerable antenna SIN = 13 3 dB/5 3 MHz-noise bandwidth for the Zi0-ft antenna These relations indicate that both the TM and AV spectra are 25 to 35 dB greater than the TV spectrum Since the effective noise band­ width for the TM and AV extractors is 100 kHz or less the subcarrier­ to-noise ratio implies that a suppression of Z0 dB is sufficient to reduce the TM and AV signals to a level comparable with the noise level With this suppression the extractor bandwidths can be made narrower there­ by minimizing the extent of TV spectrum modification by the extractors I­ The contract requirements have been met TM and AV suppression is 20 dB, and any residual TM or AV signal present is low enough to be concealed by the noise and does not appear on the TV display with noticeable coherency 2 Th d n na n PROPRIETARY TO TRW SYSTEMS GROUP TRW INC d h It b p d 4 f d h d - d I d h df yp P h I h f wh h I h d. h p P . I TRW Sy m G TRW I 2 APEX SYSTEM AND UNIT DESCRIPTION 2 1 SYSTEM DESCRIPTION The Subcarrier Extraction System consists of five modules They are a) AV estimator module b) TM estimator module c) Biphase sensing module d) Delay module e) Buffer module A brief description of these modules is included in Subsections Z 2 through 2 6 The input signals consist of the TV baseband white noise and the two interfering subcarriers located at I 024 MHz and 1 25 MHz (See the system block diagram Figure 2-1 ) The I 0Z4-MHz subcarrier is a biphase signal modulated at a I 6-kbit or a 51 6-kbit rate and the 4 25-MHz subcarrier is an FM-FM signal modulated by a set of baseband signals including a number of analog bio-med signals and voice The unprocessed signal is fed through a buffer amplifier into the time delay network and then into the output amplifier to the summation point The unprocessed signal is also fed to the coherent amplitude detector in the biphase sensing module whose output is fed to the TM unit The two amplitude phase extractor (APEX) units are connected in a parallel feedback arrangement at one common summation port Each APEX unit has an amplitude and phase estimating channel that iq spec­ trally weighted to "optimally" estimate the character of its interfering signal and to minimize disturbance to the adjacent TV baseband spectrum The input which is a combination of the two interfering subearriers the TV baseband and noise is buffered and amplified to a level which is 3 Th d n a .
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