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.
Features:
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