Broadcast

Hardware Requirements

Server-grade PC with solid state hard drive strongly recommended for on-air use.
Pentium 4 3.4 GHz CPU or faster. Intel Dual Core strongly recommended.

Operating system: Windows XP / Windows 7, 8, 10 (32 or 64-bit).
You must install Breakaway Pipeline 4.15 after installing Breakaway Broadcast on Windows 8 or 10.
 
A dedicated system is recommended for on-air use. It should be firewalled and automatic updates must be turned off, since updates could take the station off the air. Windows 10 updates can be stopped by disabling the Windows Update service.
A system with automatic updates turned off must be treated with care because of the vulnerability risk involved. People must remember that this is an on-air processor, and the fact that it’s installed on a general purpose computer means it can be acquired inexpensively, but it should not be treated as a normal computer in any other way. It is a dedicated audio processing appliance. For example, absolutely no web browsing on this system, and as little other software as possible. Keep it pristinely clean – this computer will be the one thing keeping your station of the air!
 

Recommended sound cards for MPX output:
Any sound card that supports true 192 KHz sampling rate.

The following cards have been successfully tested:
M Audio Delta Audiophile 192 (PCI)
Realtek HD audio on-board (certain motherboards. Not all support 192 KHz output)
Lynx L22 PCI
LynxTWO PCI
Marian Trace 8 PCI
Edirol FA-101 (Firewire)
ESI Juli@ PCI

Leif recently added the following sound cards:
ESI Juli@ XTe card (PCI-express)
MOTU 828mk3
MOTU Ultra-Lite mk3
They can do both firewire and USB, and they have *DC coupled* outputs, and they’re nice and stable. They’re also still available.

 

 

Spectrum Control

 

One of the most difficult tasks for an FM processor is to accurately control peaks while also accurately controlling the spectrum.

BBP


The BBP measurement was done with on-board Realtek HD audio consumer grade codecs!

8500


The notch around the pilot in this processor's output footprint does extend all the way to the buttom.

8200

O6

Xtreme

Xmini

AP2K

Peak Control is important, because legislation dictates how far your carrier is allowed to deviate inside your channel - usally +/- 75 kHz. If any peaks are not accurately controlled, average modulation must be decreased - wasting both loudness and signal-to-noise ratio. Most FM audio processors perform this task well, and Breakaway Broadcast Processor is no exception. All processors above have excellent peak control.

Spectrum Control is also important. In FM stereo, we have several subcarriers that must be protected - for example the Pilot Tone, Stereo Subcarrier, RDS subcarrier. Contaminating the spectrum of either can result in loss of stereo separation, audible distortion, poor multipath performance (bad city reception), and RDS data errors.

So, controlling both Peaks and Spectrum are equally important. Unfortunately, they're conflicting goals. Improving one sacrifices the other, and achieving both at the same time is extremely difficult.

How is Breakaway Broadcast Processor doing compared to other processors? Judge for yourself above.

Technical Specifications

Every digital processor (hardware or software) is implemented as software inside a form of a computer. However, because Breakaway Broadcast Processor is distributed as software, it is dependent on the performance of hardware it is installed in, and requires manual calibration using an oscilloscope to achieve stated performance. Proper installation is imperative, as with any audio processor.

Frequency Response: Follows pre-emphasis curve accurate to +/- 0.01dB, 30hz - 16000 Hz.

L/R Input sampling rate: 44100, 48000, 88200, 96000, 176400, 192000 Hz.

Front-end sampling rate: 44100 or 48000hz depending on chosen input rate

Back-end (clipper, MPX) sampling rate: 176400 or 192000hz depending on chosen input rate

RDS / Pilot input sampling rate: 128000, 176400 or 192000hz, Free Running. Adaptive sample rate converter built in. External Sync not necessary.

L/R output sampling rate: 44100, 48000, 88200, 96000, 176400, 192000 Hz, Free Running. Adaptive sample rate converter built in. External Sync not necessary.

Composite baseband (MPX) output sampling rate: 128000, 176400 or 192000hz, Free Running. Adaptive sample rate converter built in. External Sync not necessary.

Peak control accuracy: +/- 1% (+/- 2% in cpu optimized mode)

Internal sample word length: 32 bits

Sample rate converters: Polyphase, less than 0.05% THD

On-air delay: Minimum 400ms (small buffering, high-pass defeated). Maximum 1 second (huge buffering, 30hz high pass).

Pilot level: Adjustable from 0 to 12.0% in 0.2% steps

Pilot protection: 60dB relative to 8% pilot, +/- 3 KHz guard band (output bandwidth 16000 Hz)

Signal-to-Noise Ratio: Greater than 80dB (Bypass, de-emphasized)

Distortion: Less than 0.05% THD (Bypass, de-emphasized)

Stereo Separation: Greater than 50dB (ITU SM.1268 limiter off)

38 kHz Suppression: Greater than 50dB

RDS (57 kHz) protection: 40dB relative to 2% injection, +/- 3 KHz guard band