Monitor Audio ASW100 User Manual download pdf (Page 237)

Digital Interface Tester

4-125

AM700 Audio Measurement Set User Manual

The menu choices here control the low frequency jitter rejection bandwidth, the

jitter gain, and the equalization feature.

LF Rejection - 120 Hz. When selected, filters out jitter below 120 Hz.

LF Rejection - 1200 Hz. When selected, filters out jitter below 1200 Hz. This filter

attenuates the lower frequency jitter components and is used when those compo-

nents are excessive.

Jitter Gain. Toggles between X1 gain and X8 gain only in jitter spectrum mode. Gain

is applied to the jitter signal before it gets to the ADC. Since the ADC is only eight

bits, small jitter levels might require this amplification. The most sensitive

measurements are made in X8 gain with the 120 Hz filter in place.

Jitter Spectrum Measurement—Equalization. Toggles between Bypassed (the desired

state) and Active. The equalization circuit suppresses some forms of jitter

introduced by cable effects, so you will usually not want to enable it. However,

some signals might be so bad that the hardware cannot lock to it unless equalization

is enabled. You will rarely need to use equalization.

Subframe Format

Preamble

Preamble Aux

20-bit audio sample word

24-bit audio sample word

LSB MSB V U C P

V Validity bit

U User data bit

C Channel status bit

P Parity bit

Aux Auxiliary sample bits

78340272831

27 28 31340

Figure 4-69: AES serial digital subframe formats

Eye/Jitter

Detection

1 2 ... 232 233 234 235 236 237 238 239 240 241 242 ... 317 318

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Monitor Audio ASW100 User Manual Page 237