Shure Phonograph TTR-103 User Guide

222 HARTREY AVE.. EVANSTON.

IL.

60204 U.S.A.

Model TTR-103

AREA CODE 3121866.2200 CABLE: SHUREMlcRo TWX: 910-231-0048 TELEX. 72-4381

SHEET

Trackability Test Record

The TTR-103 contains three trackability" tests:

1. 10.8 kHz pulsed high-frequency test with a 270 Hz repetition rate trackability and distortion test.

2. The 1000 Hz plus 1500 Hz mid-frequency trackability and distortion test.

The 400 Hz plus 4000 Hz low-frequency trackability and distortion test.

These tests

Turntable Speed 45 rpm**

Pulsed 10.8 kHz Pulsed 10.8 kHz Pulsed 10.8 kHz Pulsed 10.8 kHz 1000 1000 1000 1000

Pulsed 10.8 kHz Right Channel 1 Pulsed 10.8 kHz Right Channel 2 Pulsed 10.8 kHz Right Channel 3 24 Pulsed 10.8 kHz Right Channel 4 30

400 400 400 400

The ability of a pickup to track can be determined three ways: distortion measurements, visually on an oscilloscope, and audibly by listening. For best results, it is suggested that all three means be employed.

aDDear on the record as shown in the table below:

. .

FREQUENCY

1500 Hz

4000 Hz Lateral 5

4000 Hz Lateral

-t

4000 Hz Lateral

4000 Hz Lateral 8 30

MAXIMUM PEAK

VELOCITY

(CM

BAND

(Side 1)

Left Channel 1 15 Left Channel 2 19 Left Channel 3 24 Left Channel 4 30 Lateral 5 20 Lateral Lateral Lateral 8 40

(Side 2)

6 7

31.5

SEC)

DISTORTION MEASUREMENTS

If a pickup mistracks any of these tests, distortion components are generated and distortion percentages can be defined.

A. 10.8 kHz Pulsed High-Frequency Test

The distortion component of this test appears at the repetition rate (270 Hz), and a distortion percentage can be defined as:

Voltage at 270 Hz

DHlciH

The necessary voltages are obtained with The

bandpass width settings for the 10.8 kHz and 270 Hz voltages should be 1000 Hz and 30 Hz, respectively.

1 kHz + 1.5 kHz Mid-Frequency Test

The distortion components of this test appear at the sum (2500 Hz) and difference (500 Hz) frequencies of the signal component frequencies. A distortion percentage is defined as:

The necessary voltages are obtained with a wave analyzer.*** The

bandpass width setting for the 500 Hz, 1000 Hz, 1500 Hz, and 2500 Hz voltages is 100 Hz.

400 Hz

The distortion of the 400 as it adheres to the SMPTE*

THE DISTORTION PERCENTAGES VERSUS RECORDED VELOCITIES MAY BE PLOTTED TO PROVIDE A GRAPHIC PRESENTATION FOR EASY COMPARISONS.

VISUAL DETERMINATION OF MISTRACKING

Mistracking of a pickup for the high-frequency test can be determined by first passing the pickup output through a narrow-band filter

centered at 270 Hz then displaying the filtered output on an oscilloscope. Any sudden change in the level of this output indicates tracking.

The mid- and low-frequency tests are best presented in a

play (vertical modulation) indicates mistracking.

AUDIBLE DETERMINATION OF MISTRACKING

A tonal change will occur in each of these tests when the pickup mistracks.

'The term "trackability" refers to the ability of a phono pickup to reproduce h~gh- *'This record has been recorded for

level program material The trackabil~ty limit of a plckup at any glven tracking force and frequency is the stylus tip loses contact wlth one or both of the groove walls. Th~s loss of contact results ~n severe d~stortion of the recorded program mater~al.

27A998

(SE)

kHz Test

4000 Hz low-frequency test is best determined using an Amplitude Intermodulation Distortion Analyzer,

* *

def~ned as the modulat~on velocity (measured in cmlsec) at which

1979,

SHURE BROTHERS

INC.

wave analyzer.***

DMID

intermodulation distortion input requirements.

Voltage at 2500 Hz

Voltage at 1000 Hz

Voltage at 10.8 kHz

Voltage at 500 Hz

Voltage at 1500 Hz

Lissajous display. Any sudden change in the output at right angles to the dis-

s~dual d~stortion levsl of the test signals due to tracing inaccuracies.

***Care must be taken not to clip the input of the wave analyzer or associated

ampi~f~er.

****

Soc~ety of Motion Picture &Television Engineers

100%

rpm playback in order to minimize the re-

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