2017 NAB Introduction!
Optimod-FM 8700i: Features
Large (quarter-VGA) active-matrix color liquid crystal display (LCD)
Makes setup, adjustment and programming of the 8700i easy. Navigation is by a miniature joystick, two dedicated buttons and a large rotary knob. The LCD shows all metering functions of the processing structure in use.
Used to navigate through a menu that lets you recall a preset, modify processing (at three levels of expertise), or to access the system's setup controls.
Absolute Control of Peak Modulation
Universal transmitter protection & audio processing for FM broadcast
The 8700i provides universal transmitter protection and audio processing for FM broadcast. It can be configured to interface ideally with any commonly found transmission system in the world, analog or digital.
The 8700i provides pre-emphasis limiting for the internationally used pre-emphasis curves of 50 µs and 75 µs. Compared to its predecessor, its new clipping/pre-emphasis-control technology preserves 2.5 to 3 dB more frequency energy while significantly reducing audible clipping distortion at all frequencies. This produces a clean, open sound whose subjective brightness more closely matches the original program.
Tight peak control at all its outputs
The 8700i achieves extremely tight peak control at all its outputs — analog, AES3 (for both the analog FM and HD channels) and composite baseband.
Stereo encoder integrated with audio processing
Eliminates the overshoot problems that waste valuable modulation in traditional external encoders.
The stereo encoder has two outputs with independent level controls, each capable of driving 75 Ω in parallel with 47,000 pF, (100 ft / 30 m of coaxial cable).
By integrating the stereo encoder with the audio processing, the 8700i eliminates the overshoot problems that waste valuable modulation in traditional external encoders.
Bandwidth limiting & overshoot compensation
The 8700i prevents aliasing distortion in subsequent stereo encoders or transmission links by providing bandwidth limiting and overshoot compensated 15 kHz low-pass filters ahead of the 8700i's audio outputs and stereo encoder.
Internal DSP-based stereo encoder
The 8700i has an internal, DSP-based stereo encoder (with a patented “half-cosine interpolation” composite limiter operating at 512 kHz sample rate) to generate the pilot tone stereo baseband signal and control its peak level. The composite limiter is a unique, "you can only do this in DSP" process that beats composite clippers by preserving stereo imaging while fully protecting the stereo pilot tone, RDS/RBDS and subcarriers.
Loudness and True Peak Control
The digital radio and analog FM processing chains each include an ITU-R BS.1770-3 Loudness Meter and Loudness Controller for use in countries that enforce a BS.1770 loudness limit on digital radio broadcasts.
The 8700iHD implements “true peak” control in the HD processing chain by oversampling the HD peak limiter's sidechain at 256 kHz. This allows the 8700i to prevent clipping in a playback device's analog signal path by predicting and controlling the analog peak level following the playback device's reconstruction filter to an accuracy of better than 0.5 dB. For typical program material, accuracy is 0.2 dB.
A 192 kHz AES3 digital composite output that is compatible and interoperable with the 192 kHz standard being implemented by several transmitter manufacturers. These implantations use the left audio channel of the AES3 connection to carry the baseband, but their 96 kHz Nyquist frequency makes them unable to convey 92 kHz SCAs without aliasing. Orban’s fully backward-compatible implementation extends the standard by using the right audio channel of the link to provide bandwidth extension that accommodates the full 0-99 kHz baseband when used with hardware designed to use this extra information.
Two additional SCA inputs that are digitized and can be summed into the digital composite outputs.
A 10 MHz reference input allows the stereo pilot tone frequency and digital composite output sample rate to be locked to a 10 MHz reference signal (like GPS), facilitating single-frequency-network operation.
Analog & AES3 left/right digital inputs & outputs
OPTIMOD-FM 8700i is supplied with analog and AES3 digital inputs and outputs. The digital input and the two digital outputs are equipped with sample rate converters. The pre-emphasis status and output levels are separately adjustable for the analog and digital outputs. Each output can emit the analog FM processed signal, the analog FM processed signal with diversity delay applied, the digital radio processed signal or the low-delay monitor signal.
A loop-through connection (from the AES#2 output to the AES sync input) is provided to enable a ratings encoder (such as Arbitron®) to be inserted after the AGC, or between the output of the audio processing and the input to the stereo encoder.
Dante™ Audio-Over-IP Connectivity
100% AES67 compliant, Dante uses a dedicated Ethernet connection for two stereo audio inputs and two stereo outputs, each with a dedicated level control. Sample rate conversion is provided for both the inputs and the outputs. AES67 compliance allows the 8700i to interoperate with many other devices, and more and more proprietary networks and networked devices are being upgraded by their manufacturers to support AES67 connectivity.
Defeatable diversity delay
A defeatable diversity delay can delay the FM analog processing output up to 16.2 seconds. Delay can be trimmed in intervals of one sample of 64 kHz to match the analog and digital paths in the HD Radio system, eliminating the need to use the delay built into the HD Radio exciter and permitting the 8700i's internal stereo encoder and composite limiter to drive the analog FM exciter. Both the 8700i and 8700iFM offer this feature, making it convenient to use the 8700iFM in dual-processor HD installations where the digital channel receives independent processing from a processor like Orban's OPTIMOD 6300 or OPTIMOD-PC. Each output (Analog, Digital 1, Digital 2, Composite, and Dante) can be independently configured to emit the delayed or undelayed signal.
AES11 sync input
An AES11 sync input allows you to synchronize the output sample rate of either (or both) AES3 outputs to this input. You can also synchronize the outputs to the AES3 digital input or to 8700i's internal clock. The sync source of each AES3 output is independently selectable.
Transformerless, balanced 10 kΩ instrumentation-amplifier circuits
The analog inputs are transformerless, balanced 10 kΩ instrumentation-amplifier circuits.
The analog outputs are transformerless balanced and floating (with 50 Ω impedance) to ensure highest transparency and accurate pulse response.
Two independent analog composite baseband outputs
The 8700i has two independent composite baseband outputs with digitally programmable output levels. Robust line drivers enable them to drive 100 feet of RG59 coaxial cable without audible performance degradation.
Two analog subcarrier inputs
The 8700i's two subcarrier inputs are mixed with the output of the 8700i's stereo encoder before application to the composite output connectors. One input can be re-jumpered to provide a 19 kHz pilot reference output. Both inputs have internal level trims to accommodate subcarrier generators with output levels as low as 220 mV.
Precise control of the audio bandwidth
The 8700i precisely controls the audio bandwidth of its analog FM processing to 16.5 kHz. This prevents significant overshoots in uncompressed digital links operating at a 44.1 kHz-sample rate or higher and prevents interference to the pilot tone and RDS (or RBDS) subcarrier. The bandwidth of the 8700i's digital radio output is adjustable in 1 kHz increments between 15 kHz and 20 kHz.
Defeatable multiplex power limiter
The 8700i has a defeatable multiplex power limiter that controls the multiplex power to ITU-R BS412 standards. An adjustable threshold allows a station to achieve maximum legal multiplex power even if the downstream transmission system introduces peak overshoots into the 8700i-processed signal. Because this limiter closes a feedback loop around the audio processing, it allows the user to adjust the processor's subjective setup controls freely without violating BS412 limits, regardless of program material.
The multiplex power limiter acts on all outputs (not just the composite output). In its most common configuration, it reduces clipper drive when it reduces power, simultaneously reducing clipping distortion. However, to accommodate customers who wish to use heavier clipping to achieve a certain sound, the MPX power controller can be configured to reduce gain after the clippers.
Because of broadcaster interest in this topic, we have implemented an experimental compatible single sideband/vestigial sideband mode in the 8700i's stereo encoder. SSB/VSB operation suppresses the upper sideband of the stereo subcarrier above 38,150 Hz, which reduces the occupied bandwidth of the FM-modulated RF signal. In SSB/VBS mode, the subchannel modulator acts as a pure SSB generator for L-R material in the frequency range of 150 Hz to 17 kHz and as a vestigial sideband generator below 150 Hz.
All input, output and power connections are rigorously RFI-suppressed to Orban's traditional exacting standards, ensuring trouble-free installation.
International safety and emissions standards
The 8700i is designed and certified to meet all applicable international safety and emissions standards.
Adaptability through Multiple Audio Processing Structures
A processing structure is a program that operates as a complete audio processing system. Only one processing structure can be on-air at a time, although all are active simultaneously to permit mute-free switching between them. The 8700i realizes its processing structures as a series of high-speed mathematical computations made by Digital Signal Processing (DSP) chips. By minimizing coupling between the control microprocessor and the DSP hardware, this architecture achieves outstanding reliability.
Six processing structures
The 8700i features six processing structures. Four of these are the same as OPTIMOD-FM 8500: Five-Band (or “Multiband”) for a consistent, "processed" sound with 17 ms delay (typical), Low-Latency Five-Band (12 ms delay), Ultra-Low-Latency Five-Band (3.7 ms delay) and Two-Band (17 or 22 ms delay) for a transparent sound that preserves the frequency balance of the original program material. A special Two-Band preset creates a no-compromise "Protect" function that is functionally similar to the “Protect” structures in earlier Orban digital processors.
Two "MX" structures
The 8700i's two new "MX" structures (five-band and two-band) are similar to their 8500 counterparts except that they use the 8700i's MX peak limiting technology to decrease distortion while achieving substantial improvements in transient punch and high frequency clarity. This advanced technology requires more input-to-output delay than the older structures, so it is impractical for talent to monitor these structures off-air with headphones. The 8700i offers a special low-delay monitor output for this purpose.
The 8700i's Two-Band processing structures can be made phase-linear to maximize audible transparency.
The 8700i rides gain over an adjustable range of up to 25 dB, compressing dynamic range and compensating for both operator gain-riding errors and gain inconsistencies in automated systems.
Increase density and loudness
The 8700i can increase the density and loudness of the program material by multiband compression, limiting and clipping — improving the consistency of the station's sound and increasing loudness and definition remarkably, without producing unpleasant side effects.
The 8700i can be remote-controlled by 5 - 12V pulses applied to eight programmable, optically isolated GPI (general-purpose interface) ports.
Serial port #1
The 8700i is equipped with a serial port to interface to an WIndows® computer running Orban's PC Remote software. The connection can be either direct or through an external modem.
Serial port #2
The 8700i has a second serial port that allows the user to set up security and communications parameters through a simple ASCII terminal program running on any PC.
Built-in 100 Mbps Ethernet port
The 8700i can be connected through its built-in 100 Mbps Ethernet port to a TCP/IP network.
The SNMP (Simple Network Management Protocol) features allow you to adjust the diversity delay, monitor the 8700i's status, and send Alarm notifications via the 8700i's Ethernet connection to your network.
The 8700i includes a Telnet client that allows presets to be recalled via batch files using the free PuTTY and Plink applications. The commands are simple ASCII strings, facilitating interface to automation systems that can emit such strings through an Ethernet or RS232 serial connection.
PC Remote control software
8700i PC Remote software is a graphical application that runs under Vista, 7, 8, and 10. It communicates with a given 8700i via TCP/IP over modem, direct serial and Ethernet connections. You can configure PC Remote to switch between many 8700is via a convenient organizer that supports giving any 8700i an alias name and grouping multiple 8700is into folders. Clicking an 8700i's icon causes PC Remote to connect to that 8700i through an Ethernet network, or initiates a Windows Dial-Up or Direct Cable Connection if appropriate. The PC Remote software allows the user to access all 8700i features and allows the user to archive and restore presets, automation lists and system setups (containing I/O levels, digital word lengths, GPI functional assignments, etc.).
Bypass Test Mode
A Bypass Test Mode can be invoked locally, by remote control (from the 8700i’s GPI port, its PC Remote application, or ASCII API), or by automation to permit broadcast system test and alignment or “proof of performance” tests.
Built-in line-up tone generator
The 8700i contains a built-in line-up tone generator, facilitating quick and accurate level setting in any system.
Versatile real-time clock
The 8700i contains a versatile real-time clock, which allows automation of various events (including recalling presets) at pre-programmed times. To maintain accuracy, this clock can be automatically synchronized via the Internet to a reference time source.