studer D19 MicValve studer d19 echo canceller

Studer D19
Echo Canceller
Studer D19
The Echo Canceller
The Studer Echo Canceller is a reliable and easy-to-use system for a
problem in digital live broadcasting: monitoring signals return to
the commentator with a noticeable delay. The resulting irritating
echo effect is suppressed with the Echo Canceller.
Compensates satellite and MPEG Codec processing delays
Automatically adapts to delays of up to 1 second
Easy operation with automatic or manual delay setting
Compact Studer D19 design
– The Echo Canceller is operated locally with a few frontpanel elements. – A 3-digit delay indicates the currently selected pre-delay in the range of 0...999 msec. – With the mode switch one of the following modes can be selected:
CONT
In continuous mode the pre­delay circuit is adapting automa­tically to the current situation. The delay line is set after having detected a reliable correlation between local and return signal. This mode is selected for envi­ronments with changing configu­rations.
Operation
Digital transmission in outside broadcast has a number of
obvious advantages but also some unwanted side effects. In
complex live broadcasts the signal can sometimes be connect-
ed via cable and sometimes via satellite; in some cases the
data is transmitted in bit reduced form. Delays of up to sever-
al hundred milliseconds are the result. This becomes parti-
cularly noticeable if the broadcast signal returns to the
source as a monitoring signal.
A typical example is sport
broadcasting. The program is
switching from one location
to another, the reporter is
listening and waits. When
instructed by the control
room, he will start to
speak ... and will be con-
fronted with his own
delayed voice in his
headset.
MAN
If the installed configuration has a known delay, the manual mode will be the preferred one. It al­lows to set the pre-delay with the up and down key, to incre­ment or decrement the current delay.
ONCE
The one-shot mode is to set the delay line once, it then remains constant. It combines the advan­tages of continuous and manual mode - automatic adaption and reliable operation with low qual­ity return signals.
The problem
Location 1
Location 2
Location 3
Location 4
Trans-
mission
Line
Return Signal
On Air Signal
Central
Control Room
(Monitor)
The solution
For suppressing line reflections and feedback in telephone applications a solution in the form of a echo compensating circuit was already developed in telephone hybrid applications. Corresponding algo­rithms for the digital realisation are available, but their working range is not wide enough. The Studer Echo Canceller is looped locally (in the OB van) into the return line. By using an additional delay line (0...1 sec) the standard algorithm now works in its optimal range of 5...20 msec.
Location 1
Monitor
Local Signal
+
+
Delay
delayed return signal
The algorithms will suppress the delayed commentator sig­nal from the incoming on-air signal. The reporter hears all sound sources except his own delayed voice. In place of the suppressed signal, the local comment can be added directly, allowing the reporter to hear his own voice undelayed. The delay line can be set automatically through a cor­relation measurement from the local and delayed sig­nal, or have a fixed setting if the data are known.
Trans–
mission
Line
With the direct volume potentiometer the volume of the directly added local signal is adjusted from mute to full level.
The return signal may be bypassed to the local output by means of the bypass key.
The display field provides further information about selected modes and the status of the pre-delay adjustment.
Specifications
Input / Output
– LOCAL IN Analog line input of local source signal
XLR, balanced, transformer coupled Sensitivity -6 ... +24 dBu
– FAR IN Analog line input of return signal
XLR, balanced, transformer coupled Sensitivity -6 ... +24 dBu
– LOCAL OUT Analog line output of processed return signal
XLR, electronically balanced Sensitivity -6 ... +24 dBu
General
Sampling Rate 16 kHz Bandwidth 140...7300 Hz Compensation Range 1 sec maximum Echo Suppression typ. 15...35 dB, depending on quality of return signal Measuring Rate typ. 20...30/min.
Power Supply 90...260 V AC, 50...60Hz Mechanical Size 19" rack mount size, 1 HU
Ordering Number 60.662.001.00
Local out
Local in
Far in
to control room
level &
correlation
detector
signal
return
Acoustic
Echo
Canceller
+
+
A
D
A
D
A
D
direct
volume
delay
line
Loading...