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 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

Memo	Title	Author	Date
001	Proposal for a Cost Effective Doubling of Existing VLBI Sensitivity	A.R. Whitney	19900518
002	East Coast VLBI Group The Mark IV VLBI System – the Next Step	A.R. Whitney	19901023
003	Preliminary Mark IV Formatter Specification	A.R. Whitney	19901101
004	Comparison of OS-9 and VxWorks —		19900829
005	Another Consideration for Mark IV	D.B. Shaffer	19910106
006	Mark IV Formatter Spec. – Draft 2	A.R. Whitney	19910108
007	Limitations in recording high frequencies with the VLBA record electronics	A.E.E. Rogers	19910306
008	TAXI Fleet for MKIV and V	H.F. Hinteregger	19910314
009	ACL for Write Driver	H.F. Hinteregger	19910401
010	A magnetic circuit model for the VLBA headstack	A.E.E. Rogers	19890605
011	Wavelength Dependence of D1 and MET VLBA “Headcurves”	A.E.E.Rogers	19891227
012	Tape Noise Measurements of D1K & S-VHS	A.E.E. Rogers	19900109
013	A Quick Test of 8mm Evaporated Metal Tape (MET)	A.E.E. Rogers	19900130
014	Tests of Parallel Playback Electronics	A.E.E. Rogers, E.F. Nesman	19900202
015	Measurements of record spacing loss and numerical model to evaluate the effect of	A.E.E. Rogers, S. Deligeorges	19900627
016	Tests of a method to support thick and thin tape on a processor transport	A.E.E. Rogers, S. Deligeorges	19900627
017	Tests of the VLBA Read/Write Interface	A.E.E. Rogers, H.F. Hinteregger	19900717
018	Record Cross-talk Theory	A.E.E. Rogers, D.L. Smythe	19900717
019	Some Tests of the TI TL592B Amplifier	A.E.E. Rogers, S. Deligeorges, J. Hargreaves	19900813
020	Dummy Headstack Post for Improved Tracking Symmetry	A.E.E. Rogers, H.F. Hinteregger, P. Bolis	19900906
021	Preliminary report on First VLBA Tapes	A.E.E. Rogers, H.F. Hinteregger, D.L. Smythe, P.Bolis	19901004
022	Thin Tape Facts	H.F. Hinteregger	19901019
023	Tape winding and tape thickness non- uniformity	A.E.E. Rogers	19901130
024	Update on the AMPEX/MAXELL tape packing problem	A.E.E. Rogers	19901204
025	Edge slitting signatures and edge quality of 16 mm tapes	A.E.E. Rogers	19901204
026	Dynamic forces on the tape edge	A.E.E. Rogers	19901231
027	Tape Elastic Constant Check via Tape Winding	A.E.E. Rogers, H.F. Hinteregger	19910119
028	Methods of Measuring Headstack Gap Length	A.E.E. Rogers, H.F. Hinteregger	19910118
029	Revised Model for VLBA Head Efficiency	A.E.E. Rogers	19910131
030	Capacitance of Gapped Bars	D.L. Smythe	19910214
031	Efficiency variations in VLBA headstacks	A.E.E. Rogers	19910225
032	Scanning Electron Microscope (SEM) Gap Length Measurement	H.F. Hinteregger	19910227
033	How Head SNR Affects Reproduce Performance	D.L. Smythe	19910517
034	Calculations concerning air entrapment at the headstack and the maintenance of good head-to-tape contact	A.E.E. Rogers	19910612
035	Tape profile along the headstack	A.E.E. Rogers	19910610
036	Dynamic Friction and Viscous Drag in the Vacuum Columns	A.E.E. Rogers	19910617
037	Write Driver Asymmetry Improvements	V.A. Tran, A.E.E. Rogers	19910711
038	Head to tape contact at 320 IPS with thin tape	D.L. Smythe	19910617
039	Performance of Mark IIIA Recorder at 56 kbpi	D.L. Smythe	19910618
040	Vacuum Column Air Bearing Clearance	A.E.E.Rogers	19910627
041	Tape Winding Dynamics	A.E.E.Rogers	19910708
042	Theoretical Model for Head Flying	A.E.E.Rogers	19910702
043	Simple method of measuring edge curl	A.E.E.Rogers	19910710
044	Thermal Calculations for High Tape Speeds	A.E.E. Rogers	19910715
045	Slipping Capstans	A.E.E. Rogers	19910715
046	Accelerated tape wear tests	A.E.E. Rogers	19910717
047	VLBA Write Driver at 18 Mb/s	D.L. Smythe	19910712
048	Method of contouring heads for high tape speeds	A.E.E. Rogers	19910731
049	Spacing loss from uneven wear of headstacks	A.E.E. Rogers, H.F. Hinteregger	19910802
050	Magnetic Tape “Flying” Measurements vs Model	A.E.E. Rogers, J. Starr	19910823
051	Preliminary tests of various low friction Surfaces	A.E.E. Rogers	19910808
052	Quality Control Checks for Inch-Worm Drivers	D.L. Smythe	19910821
053	Modifying the VLBA Head Interface for Recording at 18 Mbs	D.L. Smythe	19910822
054	Reel Alignment Tolerance	A.E.E. Rogers	19911021
055	Reels for thin tape	H.F. Hinteregger, A.E.E. Rogers	19911023
056	Possible variations on the vacuum loop	A.E.E. Rogers	19910830
057	Additions to head flying model and comparison with measurements	A.E.E. Rogers	19910917
058	Preliminary tests of new and experimental Headstacks	A.E.E. Rogers	19910925
059	Write Drive Improvements	D.L. Smythe	19911004
060	Head wear rates with Fotoceram spacers	A.E.E. Rogers	19911021
061	Progress report on the solution to the tape edges heating problem	H.F. Hinteregger, A.E.E. Rogers	19911022
062	Mark 4 Drawings	R. Cady, E. Nesman	19911126
063	Tape (thin) and transport handling procedures	H.F. Hinteregger, A.E.E. Rogers	19910927
064	Configuration of Tape Path for Thin Tape and High Speed	H.F. Hinteregger, A.E.E. Rogers	19920212
065	Bar-code Reader on VLBA Transport	A.R. Whitney	19911129
066	The Effect of the Reel Hub on Tape Pack	H.F. Hinteregger, A.E.E. Rogers	19911212
067	Plan for accelerated testing of thin tape	A.E.E. Rogers	19920202
068	Tape Procurement Specification	A.E.E. Rogers, H.F. Hinteregger	19920303
069	Measured Tolerance on reel table alignment	A.E.E. Rogers, H.F. Hinteregger	19920305
070	Mechanical Upgrade Steps	A.E.E. Rogers, K.M.Wilson, H.F. Hinteregger	19920305
071	Mark 4 Head-Numbering Conventions	A.R. Whitney	19920414
072	Changes to MkIII Video Converter to Extend Bandwidth to 16 MHz	A.E.E. Rogers	19920505
073	Septum Interference with Precision Plate	K.M. Wilson	19920205
074	Summary of Results of Thin Tape Inspections	A.Sandler, H.Hinteregger, A.Rogers, N.Donald, D. Sousa	19920218
075	Mechanical Model for Reel Table Alignment Needed for Low Speed Running	A.E.E. Rogers	19920312
076	Head Assembly Mounting Screws Bottoming Out of the High Performance Damper	D. Fields	19920310
077	Head Flying: Expected Changes with Head Wear	A.E.E. Rogers	19920430
078	Differences in the VLBA, MkIII, & MkIV IF to Baseband Converter	A.E.E. Rogers	19920505
079	Tolerance of Tape Clearance in Vacuum Column	A.E.E. Rogers	19920507
080	Tape Edge Abrasion by Contact with Reel Flange Rims	A.E.E. Rogers	19920519
081	4-Level sampling threshold sensitivity with the Bos chip	A.E.E. Rogers	19920612
082	Some Loss Factors	A.E.E. Rogers	19920615
083	Pass Locations	D.L. Smythe	19920618
084	Channel Track Assignments	D.L. Smythe, A.R. Whitney	19920623
085	More on the abrasion of tape edges by reel flanges	A.E.E. Rogers	19920527
086	Preliminary Tape Canister Drop Tests	A.E.E. Rogers, H.F. Hinteregger	19920601
087	Some Calculations of forces experienced by tapes during shipment	A.E.E. Rogers, H.F. Hinteregger	19920601
088	Version 6 of RECON	R.J. Cappallo	19920615
089	Elastic modulus measurements for thin tapes	D.Callahan, A.E.E. Rogers	19920618
090	Interim Report on Correlator Chip Study for Mark IV Correlator	A.R. Whitney	19920623
091	Correlator Chip Internal Data Paths	J.I. Levine	19920619
092	ASIC Pricing	W. Aldrich	19920625
093	ASIC Pricing (Again)	W. Aldrich	19920616
094	Tape loop clearance tolerance	A.E.E. Rogers	19920623
095	Tape winding and stretched tape	A.E.E. Rogers	19920625
096	Wear tests on short tapes	A.E.E. Rogers	19920630
097	Factors which influence the tape wind test	A.E.E. Rogers	19920701
098	The effect of debris on tape packing	A.E.E. Rogers	19920702
099	Accelerated thin tape tests: Status Report	A.E.E. Rogers	19920706
100	Upgrade to Mark IV Data-Acquisition Capability	D. Smythe	19921013
101	Addition of acceleration to Mark IV on-chip phase-rotor	A.R. Whitney	19921027
102	Correlator software documentation	C.J. Lonsdale	19921028
103	Reproduce at 18 Mb/s – Preliminary Results	D.L. Smythe	19921104
104	Delay/phase tracking in the MKIV Correlator	A.R. Whitney	19921105
105	A simple method to measure friction in vacuum columns	A.E.E. Rogers	19920721
106	Elastic modulus in the radial direction for the tape	D. Callahan, A.E.E. Rogers	19920713
107	Edge guiding force variation with vacuum door clearance	A.E.E. Rogers	19920723
108	A physical model for the effect of relative humidity on edge	A.E.E. Rogers	19920728
109	Humidity tests of the tape canister	D. Callahan, A.E.E. Rogers	19920804
110	Capstan & Idler Alignment Tests	A.E.E. Rogers, K. Wilson	19920803
111	Cost estimate for thin tape upgrade	A.E.E. Rogers, H.F. Hinteregger, M.W. McDonough	19920804
112	Magnetic tape surface resistivity variation with relative humidity	D. Callahan, A.E.E. Rogers	19920805
113	Thin Tape Upgrade – Changes/Additions to VLBA Acquisition Memo #290	A.E.E. Rogers, H.F. Hinteregger	19920805
114	Influence of axis misalignment on edge guiding force	A.E.E. Rogers	19920807
115	Types of deposit and their dependence on humidity	A.E.E. Rogers	19920826
116	16 Passes with a 2 mm Guard Band	D.L. Smythe	19920821
117	Record Spacing Loss Measurement for D1 Tape	A.E.E. Rogers	19920923
118	Accelerated thin tape tests:Status report update	A.E.E. Rogers	19920929
119	Failure of Ampex tape under low humidity conditions	A.E.E. Rogers, H.F. Hinteregger	19921014
120	Theoretical wear profiles for headstacks with soft spacers	A.E.E. Rogers, H.F. Hinteregger	19921007
121	Mark 4 Station Unit — Preliminary Specification	R. Cappallo, A.R. Whitney	19921027
122	Lag-dependent phase corrections	A.E.E. Rogers	19921116
123	Implementation of Delay/phase tracking in MKIV Correlator	A.R. Whitney	19921120
124	NFRA-ITR 199 on Correlator Architectures (NFRA ITR 199)	A. Bos	19921001
125	Notes on the Dual 2*2 Chip Layout	J.I. Levine	19921201
126	Preliminary Evaluation of a Gigabit-Rate Chip set for Data Communication (G-Link)	D.L. Smythe	19921202
127	Validity Bits and Data Normalization	B. Anderson	19921211
128	Three correlation schemes with X and Y validity	A.E.E. Rogers	19930105
129	Summary of proposed SMA correlator architecture	J.I. Levine, A.R. Whitney	19930106
130	Robust and Marginal Tapes:The Shape-of-Edge Difference, Extreme Wind and Shuttle Tests, High Tg Ampex Samples Looking good	H.F. Hinteregger	19930108
131	Update of Self-Packing Reel Specifications	H.F. Hinteregger	19921207
132	Further improvement of write driver performance	V.A. Tran, K.M. Wilson	19921231
133	Digital tone extractor normalization	A.E.E. Rogers	19930108
134	Haystack Head Stacks at 18 Mb/s	D.L. Smythe	19930111
135	Using a Single Squash Plate for Mark IV Tape Drives	D.L. Smythe	19930111
136	Vernier-Delay Control for Multiplexed Data in Correlator Array	A.R. Whitney	19930216
137	The Mark IV Tape Format – Revision 1.0	A.R. Whitney	19930217
138	Expected correlation between sign and magnitude bits	A.E.E. Rogers	19930223
139	Redesigned 32-MHz synthesizer	A.E.E. Rogers	19930301
140	The EVN/Mark IV Station Unit Requirements	B. Anderson	19930224
141	The EVN/Mark IV Station Unit: Straw-Man Design	B. Anderson	19930302
142	Numerical Coding	W. Aldrich	19930303
143	Current state of postprocessing and archive subsystem software under UNIX	C. Lonsdale	19930308
144	Headstack Specification for MK3A/VLBA/- MK4 Compat	H.F. Hinteregger	19930311
144.1	Stepped and triple-cap headstack specification for VLBI tape recorder	H.F. Hinteregger	19980720
144.2	Stepped and triple-cap headstack specification for VLBI tape recorder	H.F. Hinteregger	19980817
144.3	Stepped and triple-cap headstack specification for VLBI tape recorder	H.F. Hinteregger	20000303
145	Thin Tape Upgrade – Summary of Parts, Dwgs, Assy & Test	A.E.E. Rogers, K.M. Wilson, H.F. Hinteregger, G. Peck	19930127
146	Version 7 of RECON	R.J. Cappallo	19930127
147	Suggested BBC Oscillator Improvements	A.E.E. Rogers	19930330
148	Normalization for Mark IV with Mark III Correlator	A.E.E. Rogers	19930319
149	Correlator Chip Design Review	W.Aldrich	19930331
150	MKIII BBC AGC options for 2-bit data	A.E.E. Rogers	19930427
151	Summary of 25 May 1993 Mark IV Meeting	A.R. Whitney	19930526
152*	Summary of 27 April 1993 Mark IV Meeting	A.R. Whitney	19930429
153	The Fabrication of a High Speed Cross Point Switch	J. Goodman	19930602
154	Summary of 1 June 1993 Software Group Meeting	A.R. Whitney	19930603
155	Summary of 8 June 1993 Mark IV Meeting	A.R. Whitney	19930609
156	Performance maintenance and head wear	H.F. Hinteregger	19930804
157	Methods for further reduction in head flying and Head Wear	A.E.E. Rogers	19930524
158	Tape Packing at Low Tensions	A.E.E. Rogers, C. Lam	19930726
159	Simple method of checking reel motor torque	A.E.E. Rogers	19930802
	Revision		19930809
160	Reel servo stability margin	A.E.E. Rogers	19930802
161	An evaluation of the Jodrell bank headstacks	A.E.E. Rogers, P.G. Bolis, H.F. Hinteregger	19930802
162	Preliminary tests of modified “triple cap” contour	A.E.E. Rogers	19930812
163	Wear rates, head flying and performance of the current head design at various operating tensions	C. Lam	19930901
164	Wear rates for heads fotoceram and MN130 spacer materials	A.E.E. Rogers	19930907
165	Summary of Mark IV-related meetings – week of 7 September 1993	A.R. Whitney	19930910
166	Test procedure for R131 Read Modules and R132 Parallel Reproduce Modules	D.L. Smythe, P.G. Bolis	19930916
167	Reel Servo/Driver Configuration and Margin Analysis Recommendations for More Reliable Operation at 320 ips Maximum	H.F. Hinteregger	19930924
168	A-file format and related issues	C.J. Lonsdale	19930914
169	Transmission Line Simulator Tests	J.I. Levine	19931022
170	MKIV Root File Formats	C.J. Lonsdale	19931022
171	MK4 Formatter FPGA Configuration Control	J.I. Levine	19931022
172	Mark4/EVN Data Distribution Network Simulation	J.I. Levine	19931022
173	Linkdata program and AFIO library changes	C.J. Lonsdale	19931022
174*	Hardware Interface Specification Correlator Input Board to Backplane	D.L. Smythe, A. Bos	19931005
174.2*	REVISED (REPLACES MK4 MEMO #195)		19940321
175	System Data Interface Specification		19940407
176	Proposed phase cal extractor for upgraded formatter A/D board	A.E.E. Rogers	19910328
177	Proposed redesign of the formatter A/D buffer module	A.E.E. Rogers, E.F. Nesman	19930401
178	Notes of Mark IV Station-Unit Phase-Calibration Tone Extraction	A.R. Whitney, R.J. Cappallo, E.F. Nesman	19931027
179	Detailed format of Mark III and Mark IV track- frame header	A.R. Whitney	19931027
180	PLL Clock Driver Timing	J.I. Goodman, J.I. Levine	19931103
181	Correlator-Board Backplane-Interface Signal Requirements	W.H. Aldrich, J.I. Goodman	19931105
182	The EVNFRA Correlator: Design Considerations	A. Bos	19931001
183	DZB and EVN Correlator Data Distribution Study NFRA Note 612	R.P. Millenaar	19930315
184	Header Data Format	W.A. Aldrich	19931123
185	Revised Head Block Design	H.F. Hinteregger, A.E.E. Rogers, D.L. Smythe	19931123
186	Contours of “Triple-cap”-Heads	A.E.E. Rogers	19931020
187	Model for recorder tracking response to capstan and idler surface irregularities	A.E.E. Rogers	19931123
188	Increasing the band-width of the Mark IV preamplifier to MHz	D.L. Smythe	19931124
189	Upgrades to video converters for 16 MHz bandwidth	A.E.E. Rogers	19940111
189.1	Revision 1		19940610
190	Clock Signal from SMA Data Receivers	J.I. Levine	19931122
191	Correlator Board Hardware Specification	J.I. Goodman	19931229
192	Summary of VLSI chip-simulation Meeting	A.R. Whitney	19940112
193	Correlator Board Software Development	J.I. Goodman	19940208
194	System-level diagrams for the weak-minded	A.R. Whitney	19940211
195	Hardware Interface Specification Correlator Input Board to Backplane	D.L. Smythe	19940214
174.2*	***REPLACED BY REVISED MK4 MEMO #174.2,		19940321
196	PBU Interface to the SU and the CCC	R.J. Cappallo	19940214
197	Distributing data without a Data Distributor	D.L. Smythe	19940120
198	Serial Link Interface Specification	D.L. Smythe	19941215
199	New A-file format	C.J. Lonsdale	19940217
200	PBU to SU Hardware Interface Specification	D.L. Smythe	19940224
201	New Timing Requirements for DATA to the Correlator Board	D.L. Smythe, J.I. Goodman	19940321
202	Some of the results of the “post-mortem” performed on Headstack E80	P. Bolis	19940401
203	Recovery of Shock-Deformed Tape	H.F. Hinteregger, D.L. Smythe	19940314
204	Crosspoint Switch Functional Tests	J.I. Levine	19940603
205*	Mark IV Tape Format, Recording Modes & Compatibility	A.R. Whitney	19940712
205.2*	*205.2-6 has been superceded by Mark IV Memo #230		19941219
205.3*			19950306
205.4*			19950324
205.5*			19950404
205.6*			19950604
206	Correlator Back Plane Switching #81 Submillimeter Array Technical Memorandum	A. Dowd	19940812
207	Crate Controller to Correlator Board Software Interface	J. Goodman	19940818
207.1			19950728
208	Software Development Tasks for the HP 742 crate controller	N. Sitkoff, J. Goodman	19940824
209	Timing of Clock, Data, BOCF, and Control Signals at Correlator Backplane Pins	J. Goodman	19940914
209.1			19941212
210	Measurements of Recorder Head Profiles and Changes in the Profile with Tape Speed	S. Gross, A.E.E. Rogers, H.F. Hinteregger	19940928
211	Strategies in searching for “TOT”	R.J. Cappallo	19941107
212	The `Haystack’ 66×64 Crossbar Switch	J. Goodman	19950131
213	Much Better than Expected Thin-film MR Head Performance Observed	H.F. Hinteregger	19950325
214	Correlator Board Data and Configuration Management	A.R. Whitney	19950222
215	Modelling and Evaluation of the Current Headstack	S. Müftü	19950510
216	The Effect of Air Flow and Tension on the Exit Side Behavior of a Flat Contoured Recording Head	S. Müftü	19950509
217	Meeting with Navell	A.R. Whitney	19950526
218	Meeting with Corwil	A.R. Whitney	19950530
219	Adding Application Specific Software Routines To Core DSP Software	J. Goodman	19950602
219.1			19950728
219.2			19960501
220	Correlator Chip Pipeline Defect	W. Aldrich	19950426
221	Derivation of Linear and Quadratic Fits to an Input Spline Polynomial	R. Cappallo	19940328
222	Station Unit Spline Polynomial Evaluation	R. Cappallo	19941102
223	SYSTICK Generator	D.L. Smythe	19950824
224	System Sync Generator	D.L. Smythe	19950914
225	CMOS Correlator Preliminary Revision 0.03	J. Canaris, W. Aldrich	19931214
226	The Haystack VLSI Correlator Chip Preliminary	W. Aldrich, A.R. Whitney	19930610
227	Input Board Functional Description Preliminary	W. Aldrich	19950901
227.1			19951201
228	Final Report – Evaluation of TF/MR Head with Advanced Tape	H.F. Hinteregger	19950601
229	Contact Tape Recording with a Flat Head Contour	H.F. Hinteregger	19951208
230	Mark IIIA/IV/VLBA Tape Formats, Recording Modes and Compatibility *Supercedes Memo #205 + Revisions	A.R. Whitney	20050610
231	Report on “IACC Review Meeting”, 11-12 Jan 1996, Dwingeloo	A.R. Whitney	19960119
232	First Results of Mark IV Formatter Tests	D.L. Smythe, A.R. Whitney	19960223
233	Minutes of 1st International telecon on VLBI Recording held on 8 February 1996, 10:00 A.M.	H.F. Hinteregger	19960228
234	Correlator System Temperature Measurements	J. Goodman, K. Wilson	19960306
235	Poor image rejection in MkIV converters	A.E.E. Rogers	19960329
236	Thermal Testing of the Correlator Chip	Jian-Jin Tuan	19960430
237	NFRA Internal Technical Report, ITR 207, The Haystack Correlator Chip	A.Bos, W.Aldrich, A.Whitney	19960430
238	VLBA Test Memo No. 52, Mark 4 Format Test	J.D. Romney	19960423
239	Definition and Management of Correlator-Board DSP Routines	A.R. Whitney, J.I. Goodman	19960429
240	The Haystack 66×64 Crossbar Switch Haystack Mk IV		19960604
241	Mechanics and Tribology of Recording with a Flat Top Head	Sinan Müftü	19961008
242	Junction Temperature Tests	W. Aldrich	19961105
243	Mark IV Development Group	D.L. Smythe	19961205
244	Minutes of Telecon held November 7th, 1996, 10:05-11:30 am (EST)	H.F. Hinteregger, S. Müftü	19970109
245	Mezzanine Board Interface Specification for CFA	J.I. Goodman	19970123
246	Modeling Results on the Long Term Reliability of the Flat Head Interface	S. Müftü	19970304
247	A DSP read channel for increased linear density in VLBI tape recording	J.I. Goodman	19970321
248	The Current Status of the Thin Film Head Project	H. F. Hinteregger, S. Müftü	19970502
249	Specification footnote of Cypress Semiconductor PLL Clock driver	J.I. Goodman	19970512
250	Notes on setting of rotator/vernier-delay paramaters	A.R. Whitney	19970605
251	Clarification of Mark IV data codes	A.R. Whitney	19970605
252	Spacing-Loss vs. Speed in ‘Stepped’ and ‘Triple-Cap’ Heads	H.F. Hinteregger	19970624
253	Timing recovery and gain control for proposed DSP read channel	J.I. Goodman, H.F. Hinteregger	19970709
253.1	Timing recovery and gain control for proposed DSP read channel	J.I. Goodman, H.F. Hinteregger	19970805
254	Timing on Station Unit	W.A. Aldrich	19970721
255	SMA Correlator DSP Software	A.R. Whitney	19971104
255.1	SMA Correlator DSP Software	A.R. Whitney, J.I. Goodman	19980701
256	Initial results decoding data from tape recorded at 84Kfci	J.I. Goodman	19980115
257.1	Serial Link Cables	D.L. Smythe	19990504
258	Haystack Dry Air Kit	H.F. Hinteregger, D.W. Fields, A.E. Niell	19980606
259	Mechanical test and acceptance requirements for thin tape	H.F. Hinteregger	19980728
260	Critical Screw Protrusion Check for Headstack Mounting	H.F. Hinteregger	19981116
261	Determination of Correct Write Voltage Vc:Introduction	H.F. Hinteregger	19981116
262	Spin Physics Heads at 18 Mb/s	D.L. Smythe	19981118
263	Wear Tests of the Flat-Top Thin-Film Head by Tape Shuttling	S. Muftu	19981222
264	Evaluation of Two Triple-Cap Headstack Variants	H.F. Hinteregger	19981117
265	An Introduction to the Mark IV Data Acquisition System for Mark III Users	D.L. Smythe	19981230
266	Mark IV DAS Performance Check List	D.L. Smythe	19981228
267	Tape recorder performance test	Alan E.E. Rogers, D.L. Smythe	19981228
268	Progress report on thin-film head development	H.F. Hinteregger	19990113
269	Evaluation of Phase-2, Part-1 Heads for the thin-Film MR Head Project:Triple-Flat Assembly Contour Geometry Qualification Tests	H.F. Hinteregger, S. Muftu	19990205
270	Simulation of the Tape-Flat-Head Interface for Phase II, Part 1 of the TF-Project	S. Muftu, H.F.Hinteregger	19990203
271	Test of Flat, Thin Film, Magnetoresistive Head Arrays for VLBI Tape Recorders	S. Muftu, H.F.Hinteregger	19990412
272	Tape Drive Manual for Operation in Field and Processor Sites	D.Fields, H.F. Hinteregger	19990512
273	Stepped Head Stacks at 18 Mb/s/track	D.L. Smythe	19990616
274	Evaluation of Phase-2: Five Supplementary Tests	H.F. Hinteregger	19990908
275	Bulk Degausser Evaluations and Recommendations for VLBI	H.F. Hinteregger	19990831
276	Deformation of a Tape Subject to Uniform Pressure: No-Contact Case for VLBI	S. Muftu	19991130
277	Reading and Writing at 320 IPS with Current Head Stacks	D.L. Smythe	20000208
278	Specification for Mark IV Decoder Module	A.R. Whitney,  R.J. Cappallo	20000404
279	Mark IV Decoder Protocol	R.J. Cappallo	20041118
280	Wear testing of an experimental Metrum headstack	S. Muftu, H.F.Hinteregger,  P.A. Bolis	20000711
281	Concept for Next Generation VLBI	J. Ritakari,  H.F.Hinteregger,  P.A. Bolis	20001031
282	8 Mb/s Equalizers	D.L. Smythe	20010214
283	Mark IV Correlator Board Timing	W. Aldrich	20010316
284	280 ips Read-Only Interface, New and Existing Head Usage Recommendations	H.F. Hinteregger	20010710
285	Review of Feb-Aug ’00 Notes: High-speed Head and Interface Problems and Fixes	H.F. Hinteregger	20010710
286	Write and Write-Crosstalk Tests of 1/2-inductance Spin-Physics Prototype and Standard Metrum Heads	H.F. Hinteregger	20011010
288	Proposed revision of headstack specifications	H.F. Hinteregger, A.E. Niell, A.R. Whitney	20010712
290	Evaluation of Capstan Noise for Model 96 Tape Transport	T. Buretta	20010806
291	Recently Discovered Model Problems in the Mark 4 Correlator	R. Cappallo	20030313
292	Optimally Setting the kdiv Parameter in the Mark 4 Correlator	R. Cappallo	20030311
293	Timing Offset of the Mark 4 Formatter	D.L. Smythe	20061010