MicroPhysics Tape Tester Electronics Specification

 Overview
This specification describes the functionality of the MicroPhysics Tape Tester Electronics (TTE).  The TTE is a hardware and software test system that is flexible and extendable by the end user.  The TTE integrates a pattern generator with a digitizer, a hardware Read/Write channel incorporating write pre-compensation or write equalization, and write driver/read preamplifier circuits.

 Read/Write Modes
Two distinct modes of the read/write process are implemented.  The process for parametric measurements is different than that used for error rate measurements.

The read/write process for parametric measurements occurs as follows. Using the pattern generator and hardware Read/ Write channel, the TTE writes user-defined patterns with the ability to include write equalization and pre-compensation.  These patterns are then written to and read from tape via the write driver/read preamplifier circuits. The digitizer is used to record the read-back signal. The digitized data is then transferred to a host PC where it is analyzed in software to determine parametrics.

For error rate measurements, the hardware channel is used.  Write data is generated by the pattern generator and is routed through the hardware Read/ Write channel where write equalization or write pre-compensation can be applied.  The read data is compared, bit by bit, to the write data.  Upon detection of errors, a hardware trigger is output and the error location is written to memory for analysis and reporting.

For the Read/ Write channel supplied, the data is encoded to RLL by a software encoding algorithm.  For channels with hardware encoders and decoders, the encoding algorithm may be bypassed.

For multi-channel applications, multiple channels will be able to write simultaneously, and the read will be performed sequentially, one channel at a time.  

Specifications

I. Hardware:

Pattern Generator: 

            Speed: Up to 22.5M flux/sec

            Write Buffer Depth: 8K

            * Write Equalization: Programmable delay and width from 4ns to 30ns

Read Back Digitizer:

Speed: 64, 16, 4, 0r 1 Mega Samples/Sec. Selectable

Digitization: 12 bit

Depth: 256K sample

Anti-Alias Filter: 7 pole, maximally flat delay. – 3 db at digitizer rate divided by 2

Variable Gain Amplifier Range: > 100 : 1; 8 bit resolution

Test Output: 2V Peak to Peak Max. into 50 ohm

Read Output: 2v Peak to Peak Max. into 50 ohm

Index and Sector Outputs: .4 to 4v logic level with 1K series output impedance

AC Input Power Requirements: 105 – 125 vac; 50 – 60 HZ (Watts TBD)

Hardware Read/Write Channel:

Sync: TTL level hardware trigger is generated on data sync byte found

Trigger: TTL level hardware trigger is generated on error.

Standard Chip: System provided with SSI34P3410 channel

Maximum Channel Data Rate: 34 M Bits/Sec (Using 1,7 Code)

Daughter Card: channel chip provided on fully specified daughter card.  End user can design new daughter card to house different hardware channel

Read Preamp/Write Driver:

Provided with a 24-channel preamp/driver capable of writing up to 100 mA O-P in each channel. Multiple heads can be written simultaneously. MR bias current is adjustable from 2 mA to 20 mA. The preamp can accommodate a wide input voltage range up to 5000 mV P-P.

Read Preamp/Write Driver cards are fully specified.  End user can design new Preamp/Driver card to house different hardware.

 * Comes on standard channel card using SSI34P3410 I.C.

II. Software:

User Interface:  32 bit Microsoft Windows based.

Parametric Tests:

·        TAA (software peak follower)

·        Resolution (ratio of software peak follower for two different write patterns)

·        Overwrite (FFT based); Frequencies are user defined by software

·        PW-50 (software analysis of averaged pulse shape): Measurement capability down to 45 ns

·        Amplitude Stability (variation of TAA on repeated reads with optional write between reads)

·        Amplitude Modulation (variation of peak follower signal) with user defined time constant

·        Amplitude Asymmetry (positive vs. negative height of peak follower)

·        Pulse-Width Asymmetry (positive vs. negative PW 50)

·       Time Asymmetry (time difference between pos. to neg. peak and neg. to pos. peak)

·        RMS noise (via FFT-wide band noise measured over user defined bandwidth.  Measured using DC erase, AC erase or user defined tone)  

·        Spectral response via FFT

Error Tests:

·        Window Margin (+/- 20 percent of the bit cell)

·        Error Rate

Composite Tests:

Description: one or more parametric tests as a function of:

·        Write Current (Saturation Test)

·        MR-Current (MR Saturation Test)

·        Off Track Position

·        Head Position (any computer controlled axis)

·        Frequency 

III. Software Extensions:

MicroPhysics will develop special software for your application requirements.

IV. Hardware Extensions:

    MicroPhysics will develop preamps, channels or other hardware as required for your specifications. 

Summary
This document describes the hardware and software that compose MicroPhysics Tape Tester Electronics.  The hardware and software allow magnetic channel characterization of tape head/media systems in both engineering and manufacturing environments.  The system is extendable, both in hardware and software, to allow fast, flexible implementation of proprietary read/write channels and preamp/write driver circuits.

Flying Height 
Tester

Disk Head 
Tester-2

Head Stack Assembly (HSA) Tester

Tape Head Tester

Tape Spacing Analyzer

Helical Tester

SliderLab

TapeLabH

TapeLab