RF SUPPRESSION IN AUDIO OR CONTROL CIRCUITS
RFI Suppressed on Six Signal Conductors
The ST‑FS6 Ferrite Suppressor / RF Filter is used to attenuate excessive RF interference (RFI) induced in the wiring conductors by a nearby communications tower. The passive ST‑FS6 provides six isolated channels of highly effective ferrite RF suppression without capacitance to ground or series resistance. Two ground terminals are provided to be used as tie points for connecting cable shields (not pictured). The ground lugs have no internal connection to the suppression circuitry. Each of the six I/O terminals may be used independently for the suppression of RF on Audio, dc power or logic control signal conductors. RF interference on audio and control wiring causes unwanted audio noise or instability in control circuits. The ST‑FS6 is normally installed at the rack where signals are received. It is possible that interference may interfere with audio or control sending equipment, making it beneficial to install a suppressor module at both ends of the long interconnection lines.
DISTRIBUTE COMPUTER VIDEO SIGNALS TO MULTIPLE DISPLAYS
1x4 VGA through QXGA Distribution
Waiting rooms, airport terminals, dispatch centers, and operations hubs are just a few of the locations where multiple monitors of computer generated video are needed. The EZ‑VMD4 provides one local monitor plus three monitor outputs. Outputs offer wide RGB bandwidth for superb graphics reproduction and high resolution compatibility from VGA through QXGA. Front panel switches allow ID BIT selection and selection of TTL or Video 75 Ω sync. The compact size of the EZ‑VMD4 allows the use of this professional quality distribution amplifier even when equipment space is limited.
The EZ‑VMD4 is shipped with a high‑efficiency power supply that connects to a locking dc power jack.
LONG DISTANCE TWISTED-PAIR VIDEO MONITORING
Camera at Top of Ski Lift Monitored at Ski Lodge Security Office
The security camera at the top of the ski lift feeds an RDL TX‑TPS1C Active Three Pair Sender. At the end of about one mile of twisted pair cable,
a TX‑TPR3C Twisted Pair Receiver feeds the video monitor in the security office. The TX‑TPR3C is set to terminate the twisted pair cable. GAIN
and EQ controls are adjusted to compensate for cable losses.
Note: Two audio pairs are also available on the RDL Format C modules. No audio is shown in this application; the audio channels could be used
to provide talk‑back capability from the upper lift operator station.
AUTOMATIC RAMP OF ALARM SIGNAL
Voltage Controlled Attenuator Controls Alert Activation Tone Bursts and Receiver Noise
The RU‑VCA2A Local/Remote Controlled Audio Attenuator has an internal ramp generator which makes it ideal for switch or relay‑operated level control. In this example, the ST‑ACR1 Line‑Level Audio Controlled Relay is used to operate the RU‑VCA2A so that the activation tones sent at the start of the fire dispatch transmission are fed at reduced volume to the speakers. Full volume is reached in time for the alert message. When an alert tone is first received, the ST‑ACR1 senses audio and causes the RU‑VCA2A to ramp up the audio level. After the message is finished, the audio level is returned to minimum. The RU‑VCA2A allows front‑panel setup of both ramp up and ramp down rates. The combination of the ST‑ACR1 and RU‑VCA2A prevents random receiver noise or activation tones from bursting at full volume through the fire station sound system.
AUDIO DISTRIBUTION OVER TWISTED PAIR
Multi-Zone Paging w/BGM and Message Repeater
An RDL FP‑MR2 Message Repeater plays back pre‑recorded messages and provides ducking or muting of the BGM source during message playback. The
message repeater can be programmed to repeat automatically or may be triggered manually. Two dynamic or condenser microphones are pre‑amplified to
line‑level by an RDL HR‑MP2 Dual Microphone Preamplifier. All three audio sources (BGM/Message Repeater, Paging Mic 1, Paging Mic 2) are distributed
to each of the three floors of an office or retail building over readily available CAT5 cabling utilizing an RDL RU‑TPS4A Active Sender/Distributor and three
TX‑TPR3A Active Receivers (one per floor). Each Active Receiver provides line‑level audio to an RDL HD‑MA35A Mixer Amplifier. The BGM/Message
Repeater signal connects to Input 2 of the mixer amplifier on each floor. Input 1 of each mixer amplifier is fed from the Receiver output that corresponds
with the Paging Mic (1 or 2) that will be used to page on that floor. Input 1 is set to "duck" the other amplifier input(s) so paging will take priority.
The RDL Format‑A twisted pair products provide flexibility and expandability for this multi‑zone paging system. Additional floors may be added using
additional receiving modules and amplifiers./
Two-Zone Noise Masking System for Office Space
This application shows the layout of a two zone noise masking system. The white noise line output from the RDL ST‑NG1 feeds the inputs of two RDL FP‑PEQ3 parametric equalizers. The FP‑PEQ3 equalizers allow the installer to flatten the noise spectrum in each zone. The line output of each FP‑PEQ3 is fed through RDL FP‑PA20A 20W, 70/100 V power amplifiers. The 70 V output of each FP‑PA20A feeds multiple 70 V speakers in its associated zone. Multiple equalizers and amplifiers may be added for larger systems with more zones.
AUTOMATIC VIDEO MONITORING IN MULTIPLE ZONES
Sequential Video Switching Provides Full-Screen Images From Four Monitored Zones
RDLâ€™s RU‑VSQ4 Video Sequencing Switcher provides sequential vertical‑interval (to eliminate/minimize screen roll) switching between (up to) four video cameras, pausing from one to fifteen seconds on each image. The sequence interval is adjustable on a recessed front panel control. The RU‑VSQ4 provides a loop‑through output from each camera to facilitate connection of additional monitors or recorders. The security agent can press any source pushbutton to continuously view that particular source, then press the button again to resume sequencing. Open‑collector outputs are provided on the rear panel for audio‑follow‑video switching, tally indicators or other control.
MULTIPLE CHIMES IDENTIFY SPECIFIC ENTRANCES
RDL FP-CH8 Provides Unique Annunciator For Each Door
The RDL FP‑CH8 Chime Generator is the solution when it is necessary to associate a unique sound with specific events. In this example, four of
the eight available chime tones are used. A particular chime identifies which doorbell button is pushed.
The push button associated with each door triggers a specific chime in the FP‑CH8. The moduleâ€™s line level audio output is amplified by an RDL
ST‑PA2 audio amplifier so the chime is heard in the monitoring room.
The FP‑CH8 output could feed audio to a facility‑wide BGM/paging system. A setting on the FP‑CH8 allows the chimes to duck or to be mixed
with background music.
The eight chime tones can be sampled by clicking â€œHear me in actionâ€ on the FP‑CH8 product description page on the RDL web site.
KSU/PBX PAGING WITH BGM OVERRIDE
Paging System for Office Space with BGM Override
This example shows how to utilize a telephone line (input) port on an existing KSU to add paging from the telephone system to a background music (BGM) system. The ST‑TC1 acts as a virtual telephone line when connected to a KSU FX port. When that “line” is selected using any phone instrument connected to the KSU, the ST‑TC1 provides audio from the instrument mouthpiece to the ST‑VP2 Automatic Ducking Module. The ST‑VP2 automatically ducks the background music audio for the duration of the page, then ramps up the music at the end of the page. In this example an FP‑PA20A 70 volt amplifier is powering 70 volt loudspeakers in the office area. The ST‑TC1 provides relay contact closures when it is activated by a telephone instrument. The relay contacts can be used to provide additional functions when paging is active, including visual indicators or triggering a radio transmitter.
ELIMINATE HUM BARS FROM REMOTE CAMERA
Galvanic Isolation for Composite Video â€œGround Loopâ€
Picture quality from a locally‑powered remote video camera is easily degraded by a â€œground loopâ€. The difference in ground voltage between the video source and monitoring locations can create herringbone patterns or rolling hum bars. Small â€œground loopâ€ voltages can easily impair the quality of a 1 volt video signal. The RDL EZ‑HK2 at the receiving location removes the â€œground loopâ€ using a high quality video transformer in a shielded metal enclosure. The input jack is ground‑isolated. A ground‑lift switch allows the output jack shield to be lifted from the metal chassis if required.
POWERING MULTIPLE STICK-ONS FROM SINGLE SUPPLY
Distributed dc Power From Current-Limited Switching Power Supply
The low current consumption of STICK‑ON modules allows multiple modules to be powered from a single supply. The ST‑PD5U distributes power from any RDL current‑limited switching power supply to up to five modules with a total current requirement of 2 amperes or less. RDL 24 Vdc switching power supplies (purchased separately) are available with current ratings of 500 mA, 1 A and 2 A. All meet ENERGY STAR Level V standards.
KSU/PBX ZONE PAGING
2-Zone Paging System for Office Space
This example shows how to utilize telephone line (input) ports on an existing KSU to add two zones of paging from the telephone system. The ST‑TC1 acts as a virtual phone line when interfaced with a KSU FX port. When either â€œlineâ€ is selected using any phone instrument connected to the KSU, the associated ST‑TC1 provides an audio path from the instrument mouthpiece to the paging amplifier. In this example two FP‑PA20A 70 volt amplifiers are powering 70 Volt loudspeakers in the two office areas. The ST‑TC1 provides relay contact closures when it is activated by a telephone instrument. The relay contacts can be used to provide additional functions when paging is active, including visual indicators or triggering a radio transmitter.
MOTION MONITORING IN MULTIPLE ZONES
Aural and Visual Alerts at Security Station of Motion Detection By Zone
This application uses a motion sensor in each of four zones to trigger a corresponding RDL D‑BZR Audio Alert Module at a security station. When triggered, the D‑BZR provides a loud alert tone and visual LED indication to identify which zone actuated the alert. The D‑BZR modules are mounted in a single DC‑4G tabletop chassis. During installation, the D‑BZR may be set for the normal (loud) alert tone level, or for a reduced level for use in a confined area. It may also be set to alert only for the duration the motion sensor is active, or to latch continuously in the alert condition upon motion detection. When triggered in the latching mode, the D‑BZR provides a continuous tone and LED indication until the front‑panel reset button is pressed.
OBSERVATION ROOM AUDIO MONITOR
Loudspeaker or Headphone Listening Station for Microphones Positioned in An Observation Room
Two microphones positioned in the observation room are preamplified and mixed by the ST‑MX2 audio mixer. The line‑level output of the mixer is amplified by the D‑HPA3 3.5 watt power amplifier to feed a D‑SP1A Decora‑Style loudspeaker. The D‑HPA3 includes a separate headphone amplifier. The speaker amplifier is set (rear‑panel switch) to mute the speakers when headphones are connected. The front‑panel volume knob controls both the power amplifier and the headphone amplifier level. The high‑impedance bridging input on the D‑HPA3 allows the audio output of the mixer to also feed a recording device.
AMPLIFICATION FOR OUTDOOR POLE-MOUNT SPEAKERS
Pole Mounted Power Amp Operation in Extreme Temperatures
This outdoor parking area is equipped with speakers mounted in the lamp structures to provide music and paging coverage. Speakers in each pole are
powered by an RDL FP‑PA18H 18 Watt Hi‑Temp Audio Amplifier. The amplifier module is mounted in an unventilated watertight enclosure at the base of
each pole. The poles recieve direct sunlight causing the potential for high internal ambient air temperatures.
The highly efficient FP‑PA18H is ideally suited to this environment. It is designed for operation in ambient temperatures up to 70 degrees Celsius (about
158 degrees Fahrenheit) and contributes negligible heat to the ambient temperature inside the pole.
The amplifierâ€™s integral compressor/limiter insures maximum intelligibility by keeping average power levels high and preventing clipping. The FP‑PA18H
combines RDL's high audio performance standards with the capability of operation in harsh temperature environments.
1] If it is desired to monitor the operation of the complete system, the audio detector included in each FP‑PA18H can be wired back to the system audio rack to confirm that audio is being
received and amplified at each pole.
2] If the FP‑PA18H is acquired with an RDL power supply, that supply must be located in an ambient environment not to exceed 40 degress C. FP‑PA18H modules are available without a
power supply for use with high temperature supplies or in systems using distributed 24 Vdc power. Contact RDL Technical Support for more information.
INTERCOM USING SINGLE REMOTE SPEAKER
Speaker Serves Dual Duty as Microphone and Speaker
This intercom application reduces the hardware requirements for a secure or weatherproof call box like those found in drive‑through talkback systems or secured entryways. The ST‑IC1 Intercom Amplifier input accepts a dynamic mic or phantom powered condenser mic. It can also use an 8 Ω or a 45 Ω speaker as a microphone element. An ST‑LCR1 Logic Controlled Relay is used in this application to switch a remote speaker so that it can function alternately as a speaker and as a microphone.
NOISE MASKING WITH PAGING
Constant Voltage System for Noise Masking and Overhead Paging
Random white noise generated by the ST‑NG1 White and Pink Noise Generator is fed to Input 2 of the HD‑MA35A Mixer Amplifier. A Paging
Source is connected to Input 1 of the HD‑MA35A. The Mixer Amplifier can be programmed to attenuate (duck) the white noise by 25dB
during a paging event. Ducking can be initiated either manually, from a contact closure on the paging device, or automatically by adjusting the
Input 1 VOX sensitivity on the HD‑MA35A. The ST‑NG1 is powered directly from the 24 Vdc output on the rear of the HD‑MA35A.
CLASSROOM AUDIO OVERRIDE PAGING SYSTEM
School Paging Interrupts Classroom Audio
This system uses a TX‑PCR1 Paging Controlled Relay to interrupt classroom audio to allow a page to be heard clearly. Classroom audio is fed through a wall plate to the 70 Volt amplifier. The 70 V speaker ouput is routed through normally closed contacts of the paging controlled relay to the clasroom speakers. The paging controlled relay samples the 70 V audio to the classroom paging speaker. Whenever school‑wide paging is active the relay is energized and the classroom audio is interrupted. This allows the page to be heard without interference from the classroom audio. The wall plate used in this example is available in the normal RDL grey/white or in stainless steel with custom labeling available.
OBSERVATION ROOM AUDIO MONITOR
Loudspeaker or Headphone Listening Station for Microphones Positioned in An Observation Room
Two microphones positioned in the observation room are preamplified and mixed by the ST‑MX2 audio mixer. The line‑level output of the mixer is amplified by the D‑HPA3 3.5 watt power amplifier to feed a wall‑mounted loudspeaker. The D‑HPA3 includes a separate headphone amplifier. The speaker amplifier is set (rear‑panel switch) to mute the speakers when headphones are connected. The front‑panel volume knob controls both the power amplifier and the headphone amplifier level. The high‑impedance bridging input on the D‑HPA3 allows the audio output of the mixer to also feed a recording device.
SECURITY AND SURVEILLANCE
Remote Security Monitoring and Recording
This system gives the user the ability to monitor and record audio from a remote location. The STM‑2 Microphone Preamplifier feeds both a recorder and a monitor amplifier in the monitoring location. The 2 Watt amplifier feeds a single 8Ω speaker in the room where the recording is taking place. The remote volume control gives the user the ability to adjust the volume as needed. The wall control is offered in RDL standard white/gray or in stainless steel with custom labeling available.