PERFORMANCE SPECIFICATIONSFrequency Response
Composite/MPX Output: ±0.25dB, 20Hz–15kHz assuming the use of a lab-quality FM-multiplex decoder with the appropriate de-emphasis characteristic.
L/R Line Outputs:±0.25dB, 20Hz–15kHz through an appropriate de-emphasis network in the FM mode; ±0.25dB, 20Hz–20kHz in the Flat mode.
AES Digital Output (Digital Input): ±0.25dB, 20Hz –15kHz through an appropriate de-emphasis network in the FM mode; ±0.1dB, 20Hz–20kHz in the Flat mode
Composite/MPX Output: SNR >85dB with carrier modulation at maximum output level through an appropriate de-emphasis network.
L/R Analog Line Outputs: Residual Noise better than 100dB below the output clipping point(through an appropriate de-emphasis network in the FM mode).
AES digital Output (Digital Input): Residual noise better than 130dB below 0dBFS (through an appropriate de-emphasis network when indicated.
Composite/MPX Output: <0.01% THD using an appropriate de-emphasis network.
Line Outputs: <0.06% THD in digital and analog Line Outputs using an appropriate de-emphasis network when indicated.
Program Signal Latency:
Composite/MPX Output: >65dB, 20Hz-15kHz assuming the use of a lab-quality FM-multiplex decoder with the appropriate de-emphasis characteristic. Linear Crosstalk (main/sub or sub/main):.78dB.
L/R Analog Line Outputs: At 1dB below the output clipping level, >100dB through an appropriate de-emphasis network in the FM mode; unweighted in the Flat mode.
AES Digital Output:At 0dBFS, >130dB through an appropriate de-emphasis network in the FM mode; unweighted in the Flat mode (using the Digital Line Input).
≤4.2 milliseconds, any input to any output in any operating mode.19kHz Stereo Pilot Protection:
>65dB with reference to 9% pilot injection.38kHz Suppression:
>80dB with reference to 100% carrier modulation.57kHz RDS Subcarrier Protection:
>65dB with refernce to 5% RDS sub-carrier injection.REAR PANEL APPOINTMENTSDigital Line Input:
The AES3 stereo input (XLR) accepts program sources at sampling rates of 32kHz, 44.1kHz, 48kHz and 96kHz; 16/24-bit. Input gain is adjustable for average program levels between -5dB and -35dB, re: -20dBFS.Analog Line Inputs:
L/R active balanced/bridging (XLR) inputs accept average program line levels between -15dBu and +15dBu; +26dBu max peak level.Line Outputs:
The Digital and Analog Line Outputs may each be configured independently for 20kHz flat response, or for 15kHz 'FM' characteristics, either with pre-emphasis or normalized to flat.Digital Line Output:
The AES3 (XLR) stereo output may be adjusted between -20dBFS and 0dBFS, corresponding to 100% (peak) carrier modulation. The output sampling rate may be set to follow the Digital Line Input or forced to 32kHz, 44.1 kHz, 48kHz or 96kHz. Sampling resolution is 24 bits.Analog Line Outputs:
Active balanced (XLR) outputs are adjustable between -10dBu and +24dBu (+21.5dBm), corresponding to 100% carrier modulation; source impedance is 200 ohms.Composite/MPX Output:
Two unbalanced (BNC) outputs are independently adjustable between 0.8V p-p and 8V p-p (+11dBu), corresponding to 100% carrier modulation; source impedance is 75 ohms. Pre-emphasis may be set to 75μs, 50μs or OFF.RDS Input:
Unbalanced/bridging (BNC) input accepts a 57kHz RDS subcarrier at any level between 0.5V p-p and 5.0V p-p for a typical injection level of 5% of total carrier modulation.19kHz RDS Sync:
When RDS is enabled, the Sync Output (BNC) delivers a 5V p-p TTL-compatible square wave at the 19kHz pilot frequency; 75-ohm source.Network Port:
A RJ45 jack accepts TCP/IP network connections for remote setup and operation of the DAVID IV.Headphone Jack (Front Panel):
A quarter-inch (TRS) headphone jack allows the user to monitor the processed program audio. A volume control next to the jack adjusts the listening level.AUDIO PROCESSING FEATURESProgram High Pass:
- A user-programmable high-pass filter attenuates sub-audible noise that could compromise modulation efficiency. The filter is adjustable between 20Hz and 65Hz.
- Unobtrusive, gated ʻgain-ridingʼ AGC is quasiaverage- responding with a capture/correction range of ±18dB. Positive AGC gain may be truncated to any value between +18dB and 0dB; the AGC correction rate is programmable.
- This dual-action utility effectively broadens the soundstage for the stereo program and the centerchannel ʻsoloʼ component independently.
- Program audio is split into five frequency bands. Each band imparts both dynamic compression and adjustable static gain to afford fixed equalization and other ʻsignatureʼ control of the program audio.
PIPP™ Peak Limiter:
- Sub-bass program frequencies undergo independent dynamic compression, expansion, selective clipping and filtering for control over both static ʻRumbleʼ and dynamic ʻPunchʼ of bottom-end components.
ITU Multiplex Power Control:
- Inovonicsʼ exclusive Polarity-Independent Peak Processing assures optimum modulation of the FM carrier or other delivery channel.
- The Peak Limiter section may optionally be configured to control the r.m.s. power of the composite multiplex signal to meet the European Standard ITU-R BS.412.9.
- Fast HF limiting and distortion-cancelled clipping are each utilized to best advantage in providing independent amplitude control of program frequencies subjected to the FM pre-emphasis curve. This helps preserve program brightness and clarity despite power bandwidth constraints native to FM broadcasting.
HD Radio Delay:
- At the userʼs discretion, up to 3dB of clipping may be applied to the composite/baseband signal. Clipping is performed before the injection of the stereo pilot and RDS subcarrier.
- The composite/MPX output of the DAVID IV may be delayed between 1ms and 9.999 seconds in 1ms increments, relative to the analog and digital program line outputs when they are set to the 20kHz (Flat) output mode. When set to the FM mode(s), the line outputs are subjected to the programmed delay as well.
THE USER INTERFACEFront-Panel:
- The IP network port and supplied software allow remote setup and operation of the DAVID IV over a local network or the Internet using any Windows® PC (XP or later).
- A front-panel graphic display and jog wheel allow easy, menu-guided in-situ setup and operation of the DAVID IV. LED-bar displays indicate in/out levels and audio processing action.
- The IP network port and supplied software allow remote setup and operation of the DAVID IV over a local network or the Internet using Windows® PC (XP or later).
AC Mains Requirements: 105–130VAC or 210–255VAC, 50/60Hz; 8 watts.
Size and Weight: 1¾”H x 19”W x 13”D (1U); 9 lbs. (net) / 12 lbs. (shipping).
- 25 factory presets are provided and optimized for popular world formats, and an additional 20 custom user settings can easily be saved and shared across station networks.
AC Mains Requirements:
- 105-130 VAC or 210-255VAC, 50/60Hz; 8 watts.
Size and Weight:
- 1¾”H x 19”W x 13”D (1U); 9 lbs. (net) / 10 lbs. (shipping).