background image

11

GENx192 Studio Master Clock

Clocks, Cables and Termination

Clock Distribution: Parallel

In parallel clock distribution (word clock only), the clocks of multiple 
devices are connected to the same signal in parallel using “T” 
connectors. In a proper parallel setup, the device at the end of the 
chain is terminated (low-impedance), and all devices in between are 
unterminated (high-impedance) so as not to adversely load the  
signal down.

Parallel distribution can be used effectively, 
but it also has drawbacks:

Termination Problems:

 Some manufacturers do not clearly mark 

the termination (input) impedance of their word clock inputs. Thus 
it is quite easy to have two or more devices in the chain which are 
both terminated, causing a sharp drop in clock signal level leading 
to synchronization failure in one or more devices. The GENx192 
termination sensing LEDs are designed to aid in diagnosing problems 
with multiple terminated inputs.

Reliability:

 Having multiple cables and multiple BNC-T connectors in 

the chain can lead to a higher incidence of mechanical failure.

Lack of Flexibility:

 Many devices cannot be unterminated, and 

therefore cannot be connected together in the same parallel chain.

Clock Distribution: Serial

In serial clock distribution, clocks are chained from the output of one 
device to the input of another. Serial distribution has several drawbacks 
and should be used only for devices that have self-clocking interfaces 
(e.g. certain DAT machines and stand-alone CD burners, digital effects 
processors, etc.) These drawbacks include:

Signal Degradation:

 As the signal is passed from one device to 

another, the signal quality can become degraded the farther down the 
chain it gets.

Clock Skew:

 Devices may add a small amount of delay to the output 

signal causing the clock edge to become progressively misaligned 
between each device in the chain.

Added Jitter:

 Each device has an inherent amount of jitter in its 

internal clocks. If the device regenerates the clock rather than passing 
it through then the inherent jitter of the device will get added to the jitter 
contributed by all previous devices. Any signal quality degradation will 
only exacerbate the jitter problem.

CLOCK IN

MASTER

CLOCK OUT

CLOCK IN

SLAVE #1

CLOCK OUT

CLOCK IN

SLAVE #N

CLOCK OUT

BNC 75 Ohm

Terminator

CLOCK IN

MASTER

CLOCK OUT

CLOCK IN

SLAVE #1

CLOCK OUT

CLOCK IN

SLAVE #N

CLOCK OUT

BNC 75 Ohm

Terminator

CLOCK IN

MASTER

CLOCK OUT

CLOCK IN

SLAVE #1

CLOCK OUT

CLOCK IN

SLAVE #N

CLOCK OUT

CLOCK IN

MASTER

CLOCK OUT

CLOCK IN

SLAVE #1

CLOCK OUT

CLOCK IN

SLAVE #N

CLOCK OUT

Содержание GENx192

Страница 1: ...GENx192 Studio Master Clock User s Guide...

Страница 2: ...6408 216th Street SW Mountlake Terrace WA 98043 USA T 1 425 778 7728 F 1 425 778 7727 www SymetrixAudio com 2 User s Guide Safety...

Страница 3: ...on openings Install only in accordance with the manufacturer s instructions Do not install near any heat sources such as radiators heat registers stoves or other apparatus including amplifiers that pr...

Страница 4: ...at sample rates of up to 192 kHz The outputs are divided into two groups each having independent control over sample rate The GENx192 can also synchronize to and re distribute external word clock or...

Страница 5: ...x However when an external clock is used the switch can act as either a multiplier or divider depending on the rate of the external clock For example with an external 96 kHz clock the GENx192 generate...

Страница 6: ...or CMOS level word clock signals from 28 to 216 kHz TERM Switch Push Button Toggle Switch Enables or defeats Word Clock input termination Green TERM LED beneath the switch indicates proper Word Clock...

Страница 7: ...y of the four GENx192 AES outputs and the male end into your destination device s AES input Repeat as necessary to connect additional devices NOTE Be sure that the designated AES input of your destina...

Страница 8: ...l base rate of either 44 1 kHz or 48 kHz based upon the desired final output rate For example select 48 if you want 48 kHz 96 kHz or 192 kHz Select 44 1 if you want 44 1 kHz 88 2 kHz or 176 4 kHz Both...

Страница 9: ...the amount of aperiodicity in a clock signal and is generally measured in nanoseconds ns or 10 9 s For example a jitter free 50 kHz clock has exactly one clock cycle every 20 s 10 6 s If the period o...

Страница 10: ...lways use the correct cabling recommended for each type of clock signal Improper cabling can lead to several of the problems described previously such as clock signal degradation and jitter The longer...

Страница 11: ...parallel chain Clock Distribution Serial In serial clock distribution clocks are chained from the output of one device to the input of another Serial distribution has several drawbacks and should be...

Страница 12: ...lly lower clock voltage and one or more of the units may fail to lock to the clock Interfacing to Analog Systems Even today where the significant majority of recording and playback systems are digital...

Страница 13: ...neral use EN 55103 1 Electromagnetic compatibility Generic emission standard Part 1 Residential commercial and light industry EN 55103 2 Electromagnetic compatibility Generic immunity standard Part 1...

Страница 14: ...personal computer Said software is specifically excluded from this warranty Limitation of Liability The total liability of Symetrix on any claim whether in contract tort including negligence or otherw...

Страница 15: ...15 GENx192 Studio Master Clock...

Страница 16: ...tional purposes only and constitutes neither an endorsement nor a recommendation Symetrix assumes no responsibility with regard to the performance or use of these products Under copyright laws no part...

Отзывы: