Sonifex RB-SC2 Dual Sample Rate Converter (24-bit, 192kHz Capable)

Sonifex RB-SC2 Dual Sample Rate Converter (24-bit, 192kHz Capable)

A balanced AES/EBU, S/PDIF, and TOSlink optical level digital audio input are converted into AES/EBU, S/PDIF, and TOSlink optical level digital audio outputs using the 1U rack-mount RB-SC2 sample rate converter. The outputs' sample rate can be controlled by several external synchronization sources or by an internal clock.

The RB-SC2 is a high-performance, enhanced version of the RB-SC1 providing the following additional features:

Key Features

• It supports higher sample frequency rates up to and including 176.4kHz and 192kHz.
• It has 2 independent sample rate converter circuits that use a common clock source to set the output sample rate.
• It has 2 optional video synchronizing boards. These set the output sample rate to 48kHz which is synchronized to either an analog video signal or SDI digital video signal (HD or SD).
• A special X-Lock mode allows the unit to function as a full bi-directional sample rate converter.
• It has TOSlink optical digital audio inputs and outputs.
• It has front-panel push-button switches for all the main settings. The buttons are arranged in sets, where pressing the button advances the current selection and LED indicator.
• A serial RS232 port is included so that the RB-SC2 settings can be controlled remotely. The front panel LED indicators alter automatically when using RS232 commands.

Three pushbuttons are used to control the sampling frequency (FREQUENCY), channel status bit type (CSDATA), sync source, and mode of operation (SYNC) for the digital outputs.

The master sample frequency can be chosen between 32kHz, 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz, or 192kHz using the FREQUENCY button. The digital audio stream's embedded channel status bits are defined by the CS DATA button, which can be pushed to select between Professional Mode (PRO), Consumer Mode, or both.
Mode (CON) or to adhere to the input's mode (FOLLOW).

The SYNC button is used to select the synchronization input, from the AES/EBU sync input, the Wordclock input, or, for X-Lock, the other digital input. The X-Lock synchronization allows the unit to act as a bi-directional sample rate converter with the output of sample rate converter 1 syncing the input of sample rate converter 2 and vice versa so that they follow each other.

The application for the X-Lock mode is so that the RB-SC2 can be inserted between 2 digital devices that run at different sample rates, such as a PC recorder and a digital player. Using the RB-SC2 in X-Lock mode ensures that the 2 devices remain synchronized at all times regardless of the sample rate of the 2 devices.
The SYNC button will also select the operating mode of the unit as described below. If an optional video sync board is fitted then 2 sync LEDs light together to show the active video sync.

Master Mode

In this mode the unit receives a digital audio signal, which is passed to the sample rate converter and then re-formatted for the digital serial transmitter (IEC958). The sample rate converter clock signal is generated internally from an onboard master clock at a selectable rate (32kHz, 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz, or 192kHz).

Slave Mode

In this mode the unit is synchronized to an external source, using the digital audio sync, or to the TTL level Word Clock. The FREQUENCY LED will indicate the synchronized sample frequency and if no sync is present, no output will be generated.

Auto Mode

Here, the unit is synchronized to an external source, using the digital audio sync, or to the TTL level Word Clock. If no sync signal is present the unit runs from the onboard master clock at a rate selected by the front panel control (32kHz, 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz, or 192kHz).

Auto Lock Mode

This operates like the auto mode except that if no sync signal is present the unit will run at the closest master clock rate to the last locked incoming signal. The FREQUENCY LED will indicate the synchronized sample frequency.

When operating in sync modes, the SYNC button flashes whenever the unit is not synchronized to the incoming sync signal.

There are 2 further push-button switches (INPUT 1 & INPUT2) that are used to select the input connector used for each of the 2 sample rate converter circuits. These switches select between AES/EBU, S/PDIF, and TOSLink optical connectors. A red LED indicates when power to the RB-SC2 is on.