Lectrosonics ucr201 Operating Instructions Manual page 5

frequency response. Keep in mind that if hiss is added to
a signal, there is a psychoacoustic effect that makes the
sound seem brighter. The other side of this is that if hiss
is removed from a signal it will sound duller. Basically the
ear's detection apparatus is pre-sensitized to high fre-
quency sounds by small amounts of high frequency hiss.
Consider this effect when making a judgment about the
sound quality of various wireless systems and this
particular filter. Extensive testing has shown that this
filter is totally transparent.
PILOT TONE MUTE
The UCR201 uses a pilot tone muting technique in order
to protect against the reception of stray signals. The
Lectrosonics transmitter adds an inaudible signal, known
as the pilot tone, to the transmitted signal. The receiver
detects (and removes) the pilot tone, and is thus able to
identify the desired signal and mute all others.
When the receiver is powered up, receive audio is muted
unless a proper pilot tone is detected. The pilot tone must
be present for approximately one second before the signal
is accepted.
The PILOT TONE BYPASS mode is set from a menu
screen. In this mode, the received audio remains unmuted
regardless of the presence or absence of a pilot tone.
This mode is useful for locating a clear frequency, since
any potential interference may be heard. It may also be
used in situations where squelching behavior is undesir-
able. The PILOT TONE BYPASS disables the squelch, as
described below.
SMART SQUELCH
The UCR201 employs a sophisticated squelching system
in an attempt to deliver the cleanest possible audio during
marginal conditions of reception. Any squelching system
faces inevitable trade-offs: squelch too much and valuable
audio information may be lost, squelch too little and
excessive noise may be heard; respond too rapidly and
the audio sounds "choppy", respond too sluggishly and
syllables or entire words are cut off.
The UCR201 combines several techniques to achieve an
optimal balance, removing distracting noise, without the
squelching action itself becoming a distraction. One of
these techniques involves waiting for a word or syllable to
complete before squelching. Another incorporates recent
squelching history and recent signal strength, adjusting
squelching behavior dynamically for the most serviceable
result under variable conditions. Using these and other
techniques, the UCR201 can deliver acceptable audio
quality from otherwise unusable signals.
In the PILOT TONE BYPASS mode, the squelch system
is disabled. Received audio remains unmuted at all times
with this setting.
OUTPUT LEVEL ADJUST
A front panel menu screen allows adjusting the audio
output in 1dB steps from -50 to +10dBu using the menu
and up and down buttons.
POWER SUPPLY
The UCR201 may be operated from an external DC
source (see Specifications and Features section for
allowed voltages.) The receiver has a built in Poly-Fuse to
protect the unit. This fuse resets if the power supply is
disconnected for about 15 seconds.
LCD DISPLAY SCREEN
The display screen has four main windows. Pressing the
menu button rotates through each of these windows.
If the battery gets low on either transmitter or receiver, a
message will interrupt the display every few seconds. A
dead receiver battery will cause the receiver to mute,
cease function and DEAD BATTERY will be displayed.
After a power off, the unit defaults to the main window
and to the most recent frequency and audio settings.
These settings are retained even if the battery is re-
moved.
The display backlight is always on when plugged into an
external power source and will turn off after five minutes
of no keypress activity when on the internal battery.
POWER UP SEQUENCE
When the UCR201 is powered up, it is operational in
about one second. Audio will pass if there is an active
transmitter on the correct frequency. At power-up, the
LCD panel will automatically scroll through a series of
screens to confirm proper operation and inform you of its
state. First it will show LOCKED or UNLOCKED. (See
Locking and Unlocking the UCR201 Menu) The next
window will say Lectrosonics – (we like our name). The
third window will show the model # (UCR201) and the
firmware revision of the internal programming. The fourth
window will show which frequency block the receiver will
tune. The fifth window will be the main screen (page).
It is important to remember that the UCR201 is fully
operational during the power up sequence – you do not
have to wait for the power up sequence to finish.
POWER OFF
When the power switch is moved to the OFF position the
audio output is instantly muted (squelched).
Rio Rancho, NM – USA
UHF Wireless Diversity Receiver
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