Mark 4 Correlator Memo Series

Mark 4 Correlator

Note: The MIT Haystack Observatory Mark 4 correlator has been replaced with a new software correlator running DiFX.

The Mark 4 correlator was capable of simultaneously processing 1024Mbps data streams from up to 16 stations, performing cross-correlations on all 120 baselines. For continuum processing, 32 lags were normally processed, but the 131,000 lags available in the correlator could be flexibly reconfigured to trade number of baselines with number of lags. The original design of the correlator was targeted for the use with the tape-based Mark 4 VLBI data system, but was eventually updated to support the disk-based Mark 5 VLBI data system as well. In addition, the correlator supported real-time correlation of data transmitted electronically from stations (so-called ‘e-VLBI’), and had been used in this mode with data transmitted in real-time at up to 512Mbps from stations distributed globally.

The Mark 4 correlator was developed by the International Advanced Correlator Consortium (IACC), which divided development responsibilities between the U.S. and Europe, in a project which started in 1993 and concluded in late 1999. MIT Haystack Observatory developed the signal-processing core of the correlator, including a large ASIC chip specifically designed for high-speed VLBI processing. The Joint Institute for VLBI in Europe (JIVE), along with the Jodrell Bank Observatory, developed the ‘Station Unit’, which is responsible for reconstituting data from tape and pre-applying a model delay before transmission to the correlator core.

Mark 4 VLBI correlators formerly existed at MIT Haystack Observatory, the U.S. Naval Observatory in Washington, D.C., JIVE in The Netherlands, and at the Max Planck Institute for Radio Astronomy in Bonn, Germany. In addition, large connected-element correlators based on the Mark 4 correlator ASIC chip and board were in place at the Sub-Millimeter Array (SMA) at Mauna Kea, Hawaii, and at Westerbord, The Netherlands.

Mark 4 Correlator Memos

001Proposal for a Cost Effective Doubling of Existing VLBI SensitivityA.R. Whitney19900518
002East Coast VLBI Group The Mark IV VLBI System – the Next StepA.R. Whitney19901023
003Preliminary Mark IV Formatter SpecificationA.R. Whitney19901101
004Comparison of OS-9 and VxWorks —19900829
005Another Consideration for Mark IVD.B. Shaffer19910106
006Mark IV Formatter Spec. – Draft 2A.R. Whitney19910108
007Limitations in recording high frequencies with the VLBA record electronicsA.E.E. Rogers19910306
008TAXI Fleet for MKIV and VH.F. Hinteregger19910314
009ACL for Write DriverH.F. Hinteregger19910401
010A magnetic circuit model for the VLBA headstackA.E.E. Rogers19890605
011Wavelength Dependence of D1 and MET VLBA “Headcurves”A.E.E.Rogers19891227
012Tape Noise Measurements of D1K & S-VHSA.E.E. Rogers19900109
013A Quick Test of 8mm Evaporated Metal Tape (MET)A.E.E. Rogers19900130
014Tests of Parallel Playback ElectronicsA.E.E. Rogers, E.F. Nesman19900202
015Measurements of record spacing loss and numerical model to evaluate the effect ofA.E.E. Rogers, S. Deligeorges19900627
016Tests of a method to support thick and thin tape on a processor transportA.E.E. Rogers, S. Deligeorges19900627
017Tests of the VLBA Read/Write InterfaceA.E.E. Rogers, H.F. Hinteregger19900717
018Record Cross-talk TheoryA.E.E. Rogers, D.L. Smythe19900717
019Some Tests of the TI TL592B AmplifierA.E.E. Rogers, S. Deligeorges, J. Hargreaves19900813
020Dummy Headstack Post for Improved Tracking SymmetryA.E.E. Rogers, H.F. Hinteregger, P. Bolis19900906
021Preliminary report on First VLBA TapesA.E.E. Rogers, H.F. Hinteregger, D.L. Smythe, P.Bolis19901004
022Thin Tape FactsH.F. Hinteregger19901019
023Tape winding and tape thickness non- uniformityA.E.E. Rogers19901130
024Update on the AMPEX/MAXELL tape packing problemA.E.E. Rogers19901204
025Edge slitting signatures and edge quality of 16 mm tapesA.E.E. Rogers19901204
026Dynamic forces on the tape edgeA.E.E. Rogers19901231
027Tape Elastic Constant Check via Tape WindingA.E.E. Rogers, H.F. Hinteregger19910119
028Methods of Measuring Headstack Gap LengthA.E.E. Rogers, H.F. Hinteregger19910118
029Revised Model for VLBA Head EfficiencyA.E.E. Rogers19910131
030Capacitance of Gapped BarsD.L. Smythe19910214
031Efficiency variations in VLBA headstacksA.E.E. Rogers19910225
032Scanning Electron Microscope (SEM) Gap Length MeasurementH.F. Hinteregger19910227
033How Head SNR Affects Reproduce PerformanceD.L. Smythe19910517
034Calculations concerning air entrapment at the headstack and the maintenance of good head-to-tape contactA.E.E. Rogers19910612
035Tape profile along the headstackA.E.E. Rogers19910610
036Dynamic Friction and Viscous Drag in the Vacuum ColumnsA.E.E. Rogers19910617
037Write Driver Asymmetry ImprovementsV.A. Tran, A.E.E. Rogers19910711
038Head to tape contact at 320 IPS with thin tapeD.L. Smythe19910617
039Performance of Mark IIIA Recorder at 56 kbpiD.L. Smythe19910618
040Vacuum Column Air Bearing ClearanceA.E.E.Rogers19910627
041Tape Winding DynamicsA.E.E.Rogers19910708
042Theoretical Model for Head FlyingA.E.E.Rogers19910702
043Simple method of measuring edge curlA.E.E.Rogers19910710
044Thermal Calculations for High Tape SpeedsA.E.E. Rogers19910715
045Slipping CapstansA.E.E. Rogers19910715
046Accelerated tape wear testsA.E.E. Rogers19910717
047VLBA Write Driver at 18 Mb/sD.L. Smythe19910712
048Method of contouring heads for high tape speedsA.E.E. Rogers19910731
049Spacing loss from uneven wear of headstacksA.E.E. Rogers, H.F. Hinteregger19910802
050Magnetic Tape “Flying” Measurements vs ModelA.E.E. Rogers, J. Starr19910823
051Preliminary tests of various low friction SurfacesA.E.E. Rogers19910808
052Quality Control Checks for Inch-Worm DriversD.L. Smythe19910821
053Modifying the VLBA Head Interface for Recording at 18 MbsD.L. Smythe19910822
054Reel Alignment ToleranceA.E.E. Rogers19911021
055Reels for thin tapeH.F. Hinteregger, A.E.E. Rogers19911023
056Possible variations on the vacuum loopA.E.E. Rogers19910830
057Additions to head flying model and comparison with measurementsA.E.E. Rogers19910917
058Preliminary tests of new and experimental HeadstacksA.E.E. Rogers19910925
059Write Drive ImprovementsD.L. Smythe19911004
060Head wear rates with Fotoceram spacersA.E.E. Rogers19911021
061Progress report on the solution to the tape edges heating problemH.F. Hinteregger, A.E.E. Rogers19911022
062Mark 4 DrawingsR. Cady, E. Nesman19911126
063Tape (thin) and transport handling proceduresH.F. Hinteregger, A.E.E. Rogers19910927
064Configuration of Tape Path for Thin Tape and High SpeedH.F. Hinteregger, A.E.E. Rogers19920212
065Bar-code Reader on VLBA TransportA.R. Whitney19911129
066The Effect of the Reel Hub on Tape PackH.F. Hinteregger, A.E.E. Rogers19911212
067Plan for accelerated testing of thin tapeA.E.E. Rogers19920202
068Tape Procurement SpecificationA.E.E. Rogers, H.F. Hinteregger19920303
069Measured Tolerance on reel table alignmentA.E.E. Rogers, H.F. Hinteregger19920305
070Mechanical Upgrade StepsA.E.E. Rogers, K.M.Wilson, H.F. Hinteregger19920305
071Mark 4 Head-Numbering ConventionsA.R. Whitney19920414
072Changes to MkIII Video Converter to Extend Bandwidth to 16 MHzA.E.E. Rogers19920505
073Septum Interference with Precision PlateK.M. Wilson19920205
074Summary of Results of Thin Tape InspectionsA.Sandler, H.Hinteregger, A.Rogers, N.Donald, D. Sousa19920218
075Mechanical Model for Reel Table Alignment Needed for Low Speed RunningA.E.E. Rogers19920312
076Head Assembly Mounting Screws Bottoming Out of the High Performance DamperD. Fields19920310
077Head Flying: Expected Changes with Head WearA.E.E. Rogers19920430
078Differences in the VLBA, MkIII, & MkIV IF to Baseband ConverterA.E.E. Rogers19920505
079Tolerance of Tape Clearance in Vacuum ColumnA.E.E. Rogers19920507
080Tape Edge Abrasion by Contact with Reel Flange RimsA.E.E. Rogers19920519
0814-Level sampling threshold sensitivity with the Bos chipA.E.E. Rogers19920612
082Some Loss FactorsA.E.E. Rogers19920615
083Pass LocationsD.L. Smythe19920618
084Channel Track AssignmentsD.L. Smythe, A.R. Whitney19920623
085More on the abrasion of tape edges by reel flangesA.E.E. Rogers19920527
086Preliminary Tape Canister Drop TestsA.E.E. Rogers, H.F. Hinteregger19920601
087Some Calculations of forces experienced by tapes during shipmentA.E.E. Rogers, H.F. Hinteregger19920601
088Version 6 of RECONR.J. Cappallo19920615
089Elastic modulus measurements for thin tapesD.Callahan, A.E.E. Rogers19920618
090Interim Report on Correlator Chip Study for Mark IV CorrelatorA.R. Whitney19920623
091Correlator Chip Internal Data PathsJ.I. Levine19920619
092ASIC PricingW. Aldrich19920625
093ASIC Pricing (Again)W. Aldrich19920616
094Tape loop clearance toleranceA.E.E. Rogers19920623
095Tape winding and stretched tapeA.E.E. Rogers19920625
096Wear tests on short tapesA.E.E. Rogers19920630
097Factors which influence the tape wind testA.E.E. Rogers19920701
098The effect of debris on tape packingA.E.E. Rogers19920702
099Accelerated thin tape tests: Status ReportA.E.E. Rogers19920706
100Upgrade to Mark IV Data-Acquisition CapabilityD. Smythe19921013
101Addition of acceleration to Mark IV on-chip phase-rotorA.R. Whitney19921027
102Correlator software documentationC.J. Lonsdale19921028
103Reproduce at 18 Mb/s – Preliminary ResultsD.L. Smythe19921104
104Delay/phase tracking in the MKIV CorrelatorA.R. Whitney19921105
105A simple method to measure friction in vacuum columnsA.E.E. Rogers19920721
106Elastic modulus in the radial direction for the tapeD. Callahan, A.E.E. Rogers19920713
107Edge guiding force variation with vacuum door clearanceA.E.E. Rogers19920723
108A physical model for the effect of relative humidity on edgeA.E.E. Rogers19920728
109Humidity tests of the tape canisterD. Callahan, A.E.E. Rogers19920804
110Capstan & Idler Alignment TestsA.E.E. Rogers, K. Wilson19920803
111Cost estimate for thin tape upgradeA.E.E. Rogers, H.F. Hinteregger, M.W. McDonough19920804
112Magnetic tape surface resistivity variation with relative humidityD. Callahan, A.E.E. Rogers19920805
113Thin Tape Upgrade – Changes/Additions to VLBA Acquisition Memo #290A.E.E. Rogers, H.F. Hinteregger19920805
114Influence of axis misalignment on edge guiding forceA.E.E. Rogers19920807
115Types of deposit and their dependence on humidityA.E.E. Rogers19920826
11616 Passes with a 2 mm Guard BandD.L. Smythe19920821
117Record Spacing Loss Measurement for D1 TapeA.E.E. Rogers19920923
118Accelerated thin tape tests:Status report updateA.E.E. Rogers19920929
119Failure of Ampex tape under low humidity conditionsA.E.E. Rogers, H.F. Hinteregger19921014
120Theoretical wear profiles for headstacks with soft spacersA.E.E. Rogers, H.F. Hinteregger19921007
121Mark 4 Station Unit — Preliminary SpecificationR. Cappallo, A.R. Whitney19921027
122Lag-dependent phase correctionsA.E.E. Rogers19921116
123Implementation of Delay/phase tracking in MKIV CorrelatorA.R. Whitney19921120
124NFRA-ITR 199 on Correlator Architectures (NFRA ITR 199)A. Bos19921001
125Notes on the Dual 2*2 Chip LayoutJ.I. Levine19921201
126Preliminary Evaluation of a Gigabit-Rate Chip set for Data Communication (G-Link)D.L. Smythe19921202
127Validity Bits and Data NormalizationB. Anderson19921211
128Three correlation schemes with X and Y validityA.E.E. Rogers19930105
129Summary of proposed SMA correlator architectureJ.I. Levine, A.R. Whitney19930106
130Robust and Marginal Tapes:The Shape-of-Edge Difference, Extreme Wind and Shuttle Tests, High Tg Ampex Samples Looking goodH.F. Hinteregger19930108
131Update of Self-Packing Reel SpecificationsH.F. Hinteregger19921207
132Further improvement of write driver performanceV.A. Tran, K.M. Wilson19921231
133Digital tone extractor normalizationA.E.E. Rogers19930108
134Haystack Head Stacks at 18 Mb/sD.L. Smythe19930111
135Using a Single Squash Plate for Mark IV Tape DrivesD.L. Smythe19930111
136Vernier-Delay Control for Multiplexed Data in Correlator ArrayA.R. Whitney19930216
137The Mark IV Tape Format – Revision 1.0A.R. Whitney19930217
138Expected correlation between sign and magnitude bitsA.E.E. Rogers19930223
139Redesigned 32-MHz synthesizerA.E.E. Rogers19930301
140The EVN/Mark IV Station Unit RequirementsB. Anderson19930224
141The EVN/Mark IV Station Unit: Straw-Man DesignB. Anderson19930302
142Numerical CodingW. Aldrich19930303
143Current state of postprocessing and archive subsystem software under UNIXC. Lonsdale19930308
144Headstack Specification for MK3A/VLBA/- MK4 CompatH.F. Hinteregger19930311
144.1Stepped and triple-cap headstack specification for VLBI tape recorderH.F. Hinteregger19980720
144.2Stepped and triple-cap headstack specification for VLBI tape recorderH.F. Hinteregger19980817
144.3Stepped and triple-cap headstack specification for VLBI tape recorderH.F. Hinteregger20000303
145Thin Tape Upgrade – Summary of Parts, Dwgs, Assy & TestA.E.E. Rogers, K.M. Wilson, H.F. Hinteregger, G. Peck19930127
146Version 7 of RECONR.J. Cappallo19930127
147Suggested BBC Oscillator ImprovementsA.E.E. Rogers19930330
148Normalization for Mark IV with Mark III CorrelatorA.E.E. Rogers19930319
149Correlator Chip Design ReviewW.Aldrich19930331
150MKIII BBC AGC options for 2-bit dataA.E.E. Rogers19930427
151Summary of 25 May 1993 Mark IV MeetingA.R. Whitney19930526
152*Summary of 27 April 1993 Mark IV MeetingA.R. Whitney19930429
153The Fabrication of a High Speed Cross Point SwitchJ. Goodman19930602
154Summary of 1 June 1993 Software Group MeetingA.R. Whitney19930603
155Summary of 8 June 1993 Mark IV MeetingA.R. Whitney19930609
156Performance maintenance and head wearH.F. Hinteregger19930804
157Methods for further reduction in head flying and Head WearA.E.E. Rogers19930524
158Tape Packing at Low TensionsA.E.E. Rogers, C. Lam19930726
159Simple method of checking reel motor torqueA.E.E. Rogers19930802
160Reel servo stability marginA.E.E. Rogers19930802
161An evaluation of the Jodrell bank headstacksA.E.E. Rogers, P.G. Bolis, H.F. Hinteregger19930802
162Preliminary tests of modified “triple cap” contourA.E.E. Rogers19930812
163Wear rates, head flying and performance of the current head design at various operating tensionsC. Lam19930901
164Wear rates for heads fotoceram and MN130 spacer materialsA.E.E. Rogers19930907
165Summary of Mark IV-related meetings – week of 7 September 1993A.R. Whitney19930910
166Test procedure for R131 Read Modules and R132 Parallel Reproduce ModulesD.L. Smythe, P.G. Bolis19930916
167Reel Servo/Driver Configuration and Margin Analysis Recommendations for More Reliable Operation at 320 ips MaximumH.F. Hinteregger19930924
168A-file format and related issuesC.J. Lonsdale19930914
169Transmission Line Simulator TestsJ.I. Levine19931022
170MKIV Root File FormatsC.J. Lonsdale19931022
171MK4 Formatter FPGA Configuration ControlJ.I. Levine19931022
172Mark4/EVN Data Distribution Network SimulationJ.I. Levine19931022
173Linkdata program and AFIO library changesC.J. Lonsdale19931022
174*Hardware Interface Specification Correlator Input Board to BackplaneD.L. Smythe, A. Bos19931005
174.2*REVISED (REPLACES MK4 MEMO #195)19940321
175System Data Interface Specification19940407
176Proposed phase cal extractor for upgraded formatter A/D boardA.E.E. Rogers19910328
177Proposed redesign of the formatter A/D buffer moduleA.E.E. Rogers, E.F. Nesman19930401
178Notes of Mark IV Station-Unit Phase-Calibration Tone ExtractionA.R. Whitney, R.J. Cappallo, E.F. Nesman19931027
179Detailed format of Mark III and Mark IV track- frame headerA.R. Whitney19931027
180PLL Clock Driver TimingJ.I. Goodman, J.I. Levine19931103
181Correlator-Board Backplane-Interface Signal RequirementsW.H. Aldrich, J.I. Goodman19931105
182The EVNFRA Correlator: Design ConsiderationsA. Bos19931001
183DZB and EVN Correlator Data Distribution Study NFRA Note 612R.P. Millenaar19930315
184Header Data FormatW.A. Aldrich19931123
185Revised Head Block DesignH.F. Hinteregger, A.E.E. Rogers, D.L. Smythe19931123
186Contours of “Triple-cap”-HeadsA.E.E. Rogers19931020
187Model for recorder tracking response to capstan and idler surface irregularitiesA.E.E. Rogers19931123
188Increasing the band-width of the Mark IV preamplifier to MHzD.L. Smythe19931124
189Upgrades to video converters for 16 MHz bandwidthA.E.E. Rogers19940111
189.1Revision 119940610
190Clock Signal from SMA Data ReceiversJ.I. Levine19931122
191Correlator Board Hardware SpecificationJ.I. Goodman19931229
192Summary of VLSI chip-simulation MeetingA.R. Whitney19940112
193Correlator Board Software DevelopmentJ.I. Goodman19940208
194System-level diagrams for the weak-mindedA.R. Whitney19940211
195Hardware Interface Specification Correlator Input Board to BackplaneD.L. Smythe19940214
174.2****REPLACED BY REVISED MK4 MEMO #174.2,19940321
196PBU Interface to the SU and the CCCR.J. Cappallo19940214
197Distributing data without a Data DistributorD.L. Smythe19940120
198Serial Link Interface SpecificationD.L. Smythe19941215
199New A-file formatC.J. Lonsdale19940217
200PBU to SU Hardware Interface SpecificationD.L. Smythe19940224
201New Timing Requirements for DATA to the Correlator BoardD.L. Smythe, J.I. Goodman19940321
202Some of the results of the “post-mortem” performed on Headstack E80P. Bolis19940401
203Recovery of Shock-Deformed TapeH.F. Hinteregger, D.L. Smythe19940314
204Crosspoint Switch Functional TestsJ.I. Levine19940603
205*Mark IV Tape Format, Recording Modes & CompatibilityA.R. Whitney19940712
205.2**205.2-6 has been superceded by Mark IV Memo #23019941219
206Correlator Back Plane Switching #81 Submillimeter Array Technical MemorandumA. Dowd19940812
207Crate Controller to Correlator Board Software InterfaceJ. Goodman19940818
208Software Development Tasks for the HP 742 crate controllerN. Sitkoff, J. Goodman19940824
209Timing of Clock, Data, BOCF, and Control Signals at Correlator Backplane PinsJ. Goodman19940914
210Measurements of Recorder Head Profiles and Changes in the Profile with Tape SpeedS. Gross, A.E.E. Rogers, H.F. Hinteregger19940928
211Strategies in searching for “TOT”R.J. Cappallo19941107
212The `Haystack’ 66×64 Crossbar SwitchJ. Goodman19950131
213Much Better than Expected Thin-film MR Head Performance ObservedH.F. Hinteregger19950325
214Correlator Board Data and Configuration ManagementA.R. Whitney19950222
215Modelling and Evaluation of the Current HeadstackS. Müftü19950510
216The Effect of Air Flow and Tension on the Exit Side Behavior of a Flat Contoured Recording HeadS. Müftü19950509
217Meeting with NavellA.R. Whitney19950526
218Meeting with CorwilA.R. Whitney19950530
219Adding Application Specific Software Routines To Core DSP SoftwareJ. Goodman19950602
220Correlator Chip Pipeline DefectW. Aldrich19950426
221Derivation of Linear and Quadratic Fits to an Input Spline PolynomialR. Cappallo19940328
222Station Unit Spline Polynomial EvaluationR. Cappallo19941102
223SYSTICK GeneratorD.L. Smythe19950824
224System Sync GeneratorD.L. Smythe19950914
225CMOS Correlator Preliminary Revision 0.03J. Canaris, W. Aldrich19931214
226The Haystack VLSI Correlator Chip PreliminaryW. Aldrich, A.R. Whitney19930610
227Input Board Functional Description PreliminaryW. Aldrich19950901
228Final Report – Evaluation of TF/MR Head with Advanced TapeH.F. Hinteregger19950601
229Contact Tape Recording with a Flat Head ContourH.F. Hinteregger19951208
230Mark IIIA/IV/VLBA Tape Formats, Recording Modes and Compatibility *Supercedes Memo #205 + RevisionsA.R. Whitney20050610
231Report on “IACC Review Meeting”, 11-12 Jan 1996, DwingelooA.R. Whitney19960119
232First Results of Mark IV Formatter TestsD.L. Smythe, A.R. Whitney19960223
233Minutes of 1st International telecon on VLBI Recording held on 8 February 1996, 10:00 A.M.H.F. Hinteregger19960228
234Correlator System Temperature MeasurementsJ. Goodman, K. Wilson19960306
235Poor image rejection in MkIV convertersA.E.E. Rogers19960329
236Thermal Testing of the Correlator ChipJian-Jin Tuan19960430
237NFRA Internal Technical Report, ITR 207, The Haystack Correlator ChipA.Bos, W.Aldrich, A.Whitney19960430
238VLBA Test Memo No. 52, Mark 4 Format TestJ.D. Romney19960423
239Definition and Management of Correlator-Board DSP RoutinesA.R. Whitney, J.I. Goodman19960429
240The Haystack 66×64 Crossbar Switch Haystack Mk IV19960604
241Mechanics and Tribology of Recording with a Flat Top HeadSinan Müftü19961008
242Junction Temperature TestsW. Aldrich19961105
243Mark IV Development GroupD.L. Smythe19961205
244Minutes of Telecon held November 7th, 1996, 10:05-11:30 am (EST)H.F. Hinteregger, S. Müftü19970109
245Mezzanine Board Interface Specification for CFAJ.I. Goodman19970123
246Modeling Results on the Long Term Reliability of the Flat Head InterfaceS. Müftü19970304
247A DSP read channel for increased linear density in VLBI tape recordingJ.I. Goodman19970321
248The Current Status of the Thin Film Head ProjectH. F. Hinteregger, S. Müftü19970502
249Specification footnote of Cypress Semiconductor PLL Clock driverJ.I. Goodman19970512
250Notes on setting of rotator/vernier-delay paramatersA.R. Whitney19970605
251Clarification of Mark IV data codesA.R. Whitney19970605
252Spacing-Loss vs. Speed in ‘Stepped’ and ‘Triple-Cap’ HeadsH.F. Hinteregger19970624
253Timing recovery and gain control for proposed DSP read channelJ.I. Goodman, H.F. Hinteregger19970709
253.1Timing recovery and gain control for proposed DSP read channelJ.I. Goodman, H.F. Hinteregger19970805
254Timing on Station UnitW.A. Aldrich19970721
255SMA Correlator DSP SoftwareA.R. Whitney19971104
255.1SMA Correlator DSP SoftwareA.R. Whitney, J.I. Goodman19980701
256Initial results decoding data from tape recorded at 84KfciJ.I. Goodman19980115
257.1Serial Link CablesD.L. Smythe19990504
258Haystack Dry Air KitH.F. Hinteregger, D.W. Fields, A.E. Niell19980606
259Mechanical test and acceptance requirements for thin tapeH.F. Hinteregger19980728
260Critical Screw Protrusion Check for Headstack MountingH.F. Hinteregger19981116
261Determination of Correct Write Voltage Vc:IntroductionH.F. Hinteregger19981116
262Spin Physics Heads at 18 Mb/sD.L. Smythe19981118
263Wear Tests of the Flat-Top Thin-Film Head by Tape ShuttlingS. Muftu19981222
264Evaluation of Two Triple-Cap Headstack VariantsH.F. Hinteregger19981117
265An Introduction to the Mark IV Data Acquisition System for Mark III UsersD.L. Smythe19981230
266Mark IV DAS Performance Check ListD.L. Smythe19981228
267Tape recorder performance testAlan E.E. Rogers, D.L. Smythe19981228
268Progress report on thin-film head developmentH.F. Hinteregger19990113
269Evaluation of Phase-2, Part-1 Heads for the thin-Film MR Head Project:Triple-Flat Assembly Contour Geometry Qualification TestsH.F. Hinteregger, S. Muftu19990205
270Simulation of the Tape-Flat-Head Interface for Phase II, Part 1 of the TF-ProjectS. Muftu, H.F.Hinteregger19990203
271Test of Flat, Thin Film, Magnetoresistive Head Arrays for VLBI Tape RecordersS. Muftu, H.F.Hinteregger19990412
272Tape Drive Manual for Operation in Field and Processor SitesD.Fields, H.F. Hinteregger19990512
273Stepped Head Stacks at 18 Mb/s/trackD.L. Smythe19990616
274Evaluation of Phase-2: Five Supplementary TestsH.F. Hinteregger19990908
275Bulk Degausser Evaluations and Recommendations for VLBIH.F. Hinteregger19990831
276Deformation of a Tape Subject to Uniform Pressure: No-Contact Case for VLBIS. Muftu19991130
277Reading and Writing at 320 IPS with Current Head StacksD.L. Smythe20000208
278Specification for Mark IV Decoder ModuleA.R. Whitney,  R.J. Cappallo20000404
279Mark IV Decoder ProtocolR.J. Cappallo20041118
280Wear testing of an experimental Metrum headstackS. Muftu, H.F.Hinteregger,  P.A. Bolis20000711
281Concept for Next Generation VLBIJ. Ritakari,  H.F.Hinteregger,  P.A. Bolis20001031
2828 Mb/s EqualizersD.L. Smythe20010214
283Mark IV Correlator Board TimingW. Aldrich20010316
284280 ips Read-Only Interface, New and Existing Head Usage RecommendationsH.F. Hinteregger20010710
285Review of Feb-Aug ’00 Notes: High-speed Head and Interface Problems and FixesH.F. Hinteregger20010710
286Write and Write-Crosstalk Tests of 1/2-inductance Spin-Physics Prototype and Standard Metrum HeadsH.F. Hinteregger20011010
288Proposed revision of headstack specificationsH.F. Hinteregger, A.E. Niell, A.R. Whitney20010712
290Evaluation of Capstan Noise for Model 96 Tape TransportT. Buretta20010806
291Recently Discovered Model Problems in the Mark 4 CorrelatorR. Cappallo20030313
292Optimally Setting the kdiv Parameter in the Mark 4 CorrelatorR. Cappallo20030311
293Timing Offset of the Mark 4 FormatterD.L. Smythe20061010