Read-Write Analyzers-2585A PRML – Obsolete

Up to 1Gbit/s Guzik Programmable PRML Channel
Digital Clock Recovery
Digital parametric measurements
20 Taps Digital Equalizer
2G samples/s 8 bit ADC
Signal display with 4 Mbytes Memory
Servo Mode (with Guzik spin stands)

  • Guzik Proprietary PRML channel with data rates up to 1G bit/s
  • PRML chip integration with data rate up to 1G bit/s
  • Fast PRML channel optimization
  • Up to 1G flux/s programmable Pattern Generator
  • Bit pre-compensation with 5 ps resolution
  • 400 MHz bandwidth Spectrum Analyzer
  • Optional Differentiators

The data rate in PRML tests is very often limited by the PRML channel chip used for testing. Guzik has now developed a property PRML to test at data rate of 1Gb/s. This puts 1Gb/s test capability in your hand right away. No need to wait for PRML chips to become available. Soon Guzik channel will be the standard against which all channels will be compared.

In addition RWA-2585A PRML provides digital parametric measurements and digital scope functions. This increases the accuracy of all the measurements and reduces the test time.

A block diagram of the Guzik PRML channel is shown in Figure 1. Read back analog signal is digitized with high oversampling and stored in 4M bytes memory. This stored data is then processed to prepare test results. The speed of data processing in PRML mode is 40 M samples/s. PRML modes PR-4, EPR-4, E2PR4 can be chosen by software.

Figure 1. Guzik PRML Channel Block Diagram

PRML channel parameters (write current, bias current, read-write off-set, equalization, and precompensation) can be optimized by a one-button operation.

Figure 2 shows the error rate measurements with the Guzik PRML channel for a data rate of 1Gbit/s.

Figure 2. Off-Track Perfomance at 1 Gbit/s

The same hardware is used for digital parametric measurements such as: TAA, PW, SNR, etc. The speed of the digital data processing in this mode is 80M samples /s. The digital measurements provide accurate results of TAA and PW measurements, even with a low signal-to-noise ratio. For example, for SNR as low as 12 dB, the accuracy of the measurements for repetitive patterns is better than 1.5%, when most other measuring equipment cannot provide stable measurements. (See Figure 3 and Figure 4.)

Figure 3. One Shot Mode, 12 dB SNR

Figure 4. The Same, After Averaging

Digital measurements implemented in the Guzik RWA-2585A PRML is the new paradigm. In future Guzik Technical Enterprises will provide most measurements based upon a digital approach. This will make it easy to change algorithms, introduce new tests that can not be done by analog circuitry, change the type of data decoding of the PRML channel, etc. For the same time RWA-2585A can provide analog parametric measurements.



Wide range of PRML tests, includes (but is not limited to):

  • Bit error rate measurements
  • Off-track channel performance
  • Histograms of sampled values distribution
  • Sequential amplitude margin (SAM) tests
  • Amplitude margin error rate prediction

Non-linear transition shift (NLTS) measurements:

  • Pseudo-random pattern auto-correlation
  • Harmonic elimination

Correlation noise

Optimization of PRML channels:

  • Based on error rate measurements
  • Based on channel quality monitor
  • Customized optimization algorithms

Signal Display:

  • 2Gsamples/s 8 bits single shot mode, up to 4 Mbytes memory
  • Average mode

All industry-standard parametric measurements, based upon digital processing

Digital 20 taps Equalizer increases the accuracy of equalization and the flexibility of the PRML channel

Fast amplitude stability test with simultaneous measurements of postive and negative pulse amplitude

The Spectrum Analyzer provides frequency domain tests:

  • Overwrite
  • Spectrum analysis
  • NLTS measurements
  • Signal to noise ratio (including transitional noise)
  • Partial erasure

All tests done in WITE32











Maximum Data Rates

PRML: up to 1G bit/s

Error rate analyzer:

  • Guzik PRML channel: up to 1G bit/s
  • Chip Integration: up to 1G bit/s (limited by PRML chip capability)


Digital Parametric Measurements

Bandwidth: 0.1 to 550 MHz at -3 dB

Flatness: 0.3 to 400 MHz at ±0.2 dB

Typical non-linear distortion: better than 1%

Digital measurement accuracy (repetitive patterns):

  • TAA: ±0.5% (down to 15 dB SNR)
  • Pulse width: ±1.0% (down to 15 dB SNR)
  • SNR: ±0.2 dB (down to 15 dB SNR)
  • Modulation: ±1%
  • Crest factor: ±1%


PRML Chip Integration

Plug-in chip adapter module

Data rate: up to 1G bit/s (PRML chip limited)

PRML chips: from Cirrus Logic, DataPath, GEC Plessey, IBM, Lucent Technology, Marvell, NEC, SSI, and others.

New PRML chips integrated on request.


  • Based on channel quality monitor
  • Based on error rate measurements
  • Customized optimization algorithms

Wide range PRML Tests including

  • Bit error rate measurements
  • Off-track channel performance


Signal display

  • Single shot 2Gsamples/s, 8 bit
  • Memory: up to 4 Mbyte
  • Analog bandwidth: 0.1 to 550 MHz at -3 dB
  • Flatness: 0.3 to 400 MHz at ±0.2 dB


Analog Channel 985A PRML

Bandwidth: 0.1 to 550 MHz at -3 dB

Flatness: 0.3 to 400 MHz ±0.2 dB

Group delay: flatness 200 ps, up to 400 MHz

Programmable attenuator: 36 dB in 2 dB steps

Typical non-linear distortion: better than 1% (400 MHz, output level 300mV p/p single-ended)


  • 4 low pass or programmable filters (custom cutoff frequencies for low pass filters up to 400 MHz)
  • high/band pass filters available for popcorn noise measurement and BLS test
  • Optional differentiators: two plug-in positions with data range from 5 to 250 MHzs

Optional differentiators: two plug-in positions with a data range from 5 to 250 Mflux/s


Built-in Spectrum Analyzer

Frequency range: from 0.5 to 400 MHz
Frequency resolution: 10 Hz

Accuracy: ±0.2 dB within 70 dB dynamic range

Selectivity: Switchable:

  • 100 kHz at -3 dB; 500 kHz at -60 dB
  • 140 kHz at -3 dB, 850 kHz at -60 dB

Video bandwidth: 100 kHz

Noise floor level: better than -80 dB


Write Channel

  • Frequency Synthesizer: up to 2 GHz with better than 1 Hz resolution
  • Frequency stability: ±2.5 ppm up to 75 C, ±1 ppm/year
  • Pattern generator: Up to 1G flux/s, programmable pattern up to a maximum of 32 Kbytes of encoded data and hierarchical pattern structure
  • Pre-compensation: three pre-compensation values with a 5 ps resolution can be assigned to any bit in a pattern, or an unlimited number of pre-compensation values at 20 ps resolution can be assigned to any bit in a pattern
  • Jitter: 10 ps RMS (typical) for a random pattern


Guzik MR Head Amplifier
(refer to separate brochure for detailed specification)

  • Write data speed: more than 1Gflux/s
  • Rise/fall time of write current: < 800 ps
  • Write current: programmable 0 to 80 mA
  • Write to read recovery time: < 1.0 µs (typ.)
  • Differential voltage sense amplifier
  • Bandwidth: >400 MHz
  • MR Bias current: programmable -8 to 8 mA (+/-12 mA optional)


Head Amplifiers (commercial chip based)

  • More than 100 types available
  • Amplifiers with separate read and write chips
  • Parallel/serial control of head amplifier chip
  • TSA & CAM style cartridge designs
  • Available in variety of wire and TSA terminations.
  • Write current: programmable 0 to 80 mA in 0.02 mA steps.
  • MR read bias: programmable up to 20 mA (the range of the bias current depends upon the type of head amplifier) in 0.01mA steps or serial control of bias current.


Data Rate Options

RWA-2585A is available in two data rate options

  • 1G bit/s
  • 800M bit/s (lower cost)




  • Size: 21.6″ x 17.6″ x 7.3″
  • Weight: 39 lbs.
  • Power: 100-240 VAC (±10%, 50/60 Hz)


  • Size: 19.0″ x 17.6″ x 3.3″
  • Weight: 15 lbs

Specifications subject to change with out notice