D/A Series
QEI D/A Series is designed as both an analog transmitter and digital RF Amplifier. The D/A Series establishes a new level in analog FM transmitter performance with the advantage of being compatible with digital HD radio service. The D/A Series of analog transmitters utilizes the same Frequency Modulated Oscillator (FMO) utilized in the renowned 695 FM Exciter, to provide un-compromised audio performance at an affordable price.
The D/A Series of analog FM transmitters are "all solid state, on carrier direct FM, phase locked, frequency synthesized exciter", designed to exceed all FCC requirements for use in the FM broadcast band.
The D/A Series exciter may be programmed to operate on any 100 kHz increment in the FM band (10 kHz steps optional). Unlike some DDS modulation techniques, Direct FM "On Carrier" operation insures spurious free transmission and extremely low distortion, crosstalk, noise, and no stereo degradation. The frequency modulated oscillator (FMO) of the D/A Series has superior linearity and does not require any "pre-distortion" networks. The FMO is sealed in steel and foam to shield it from stray magnetic fields and eliminate microphonics.
The Power Amplifier (PA) of the D/A Series is unconditionally stable and will withstand any magnitude or phase of VSWR indefinitely without damage. The D/A Series is designed with components that are operated conservatively and well within their ratings.
The D/A Series is housed in a single space saving 5-1/4-inch chassis, will fit into virtually all transmitters in use and is the perfect upgrade for older systems. The D/A Series uses switching regulator and power factor correction technology to increase the overall efficiency. Separate analog meters for all critical parameters are standard on all models. Status and modulation levels are shown by LED’s. RF and audio connections are made by way of back panel connectors. A BNC for composite audio, XLR monaural audio and a Type "N" RF output connector. The PA input is rear panel accessible for use with HD Radio® exciter technology. When used with the QEI (or other manufacturer) low power mask filter, the D/A Series is perfect for low power HD Radio® operation.
The D/A Series is also ideal for alternative energy power sources. This unique capability will allow the D/A Series in either analog or HD Radio® mode to operate from most any non-commercial power source (solar, wind, battery pack, etc.) Reliability and simplicity of design and operation make the D/A Series an outstanding choice for every FM station.
A short list of features:
- Ultra Low Distortion, Crosstalk and Noise
- Broadband Design
- Frequency Synthesized
- Configure for AC or DC operation
- Unconditionally Stable Amplifier
- "VSWR Proof"
- Compact 5 1/4 inch Rack Mount Package
Technical Specifications
General
Power Output (Analog):
D/A 100:........................................... 50 to 100 Watts
D/A 250:......................................... 100 to 250 Watts
D/A 500:......................................... 100 to 500 Watts
Power Output (HD Operation):
D/A 100:.............................................. 5 to 25 Watts
D/A 250:............................................ 20 to 60 Watts
D/A 500:........................................... 20 to 125 Watts
Frequency Range: 87.5 to 108 MHz (other frequencies optional)
RF Load Impedance:................................. 50 ohms
Output Connector:......................... Type "N" Female
VSWR:.......................... 1.6:1 maximum at full power.
RF Harmonic/Spurious: Suppression meets or exceeds all FCC /DOC / CCIR specifications
Frequency Stability:.......... ±200 Hz from 0° to 50° C.
Modulation Capability:.......... Greater than ±350 kHz
Modulation Sensitivity vs. Temperature: 0.01% per degree Centigrade
Pre-Emphasis:
Standard:............................................. 75µsec (FCC)
Optional:............................................. 50µsec (CCIR)
Asynchronous AM S/N Ratio (AM Noise): -60 dBc (no FM modulation present)
Synchronous AM S/N Ratio (Incidental AM): -55 dBc with 100 % FM Modulation
Electrical/Mechanical
AC Power:............................. 85-250 VAC, 50/60Hz.
Regulation:. Switch mode with power factor correction
Power Factor:.................................................. 0.95
DC Power:................................................... 48 VDC
Ambient Temperature Range:
Operating:........................................ -15° C to +50° C
Startup:.............................................. 0° C to +50° C
Maximum Humidity:................. 95% non-condensing
Size:
5.25”H (13.35cm) x 19”W (48.25cm) x 18”D (45.7cm) Add 2.5” for Type N connector clearance
MONAURAL PERFORMANCE
Input Impedance:....................... 600 ohms balanced
CMRR:.......................................................... >60 dB
Input Level:.. +10 dBm for 75 kHz deviation at 100 Hz
Frequency Response:........ ±0.5 dB, 30 Hz to 15 kHz
THD+N:......................................... 0.025% at 400 Hz
FM S/N Ratio:.................... Greater than 75 dB below
75 kHz deviation at 400 Hz, measured in a 50 Hz to 15 kHz bandwidth with 75 µsec de-emphasis
WIDEBAND COMPOSITE PERFORMANCE
Inputs:... (1) unbalanced on rear panel, BNC connector
Input Impedance:.................................... 10K ohms
Input Level:.................... 3.5 VP-P for 75 kHz deviation
FM S/N Ratio: Greater than 75 dB below 75 kHz deviation at 400 Hz, measured in a 50 Hz to 15 kHz bandwidth with 75 µsec de-emphasis
THD+N:......................................... 0.025% at 400 Hz
Amplitude Response:....... ±0.01 dB, 30 Hz to 75 kHz
Composite Slew Rate:............ 9 v/µsec, symmetrical
Phase Response: ±0.1 degrees from linear phase, 30 Hz to 75 kHz
STEREO PERFORMANCE*
Frequency Response:........ ±0.1 dB, 30 Hz to 15 kHz
THD+N:......................................... 0.025% at 400 Hz
FM S/N Ratio: Greater than 75 dB below 75 kHz deviation at 400 Hz, measured in a 50 Hz to 15 kHz bandwidth with 75 µsec de-emphasis
Stereo Separation:...................................... >60 dB
Dynamic Stereo Separation:....................... >60 dB
Crosstalk (linear):......................................... >60 dB
Crosstalk (non-linear):.................................. >60 dB
SCA PERFORMANCE
Subcarrier Inputs: (3) total, unbalanced, BNC connectors
Subcarrier Input Impedance:.................. 10K ohms
Subcarrier Input Level: 1.0 Vrms, nominal for 10% injection
Subcarrier Amplitude Response: ±0.2 dB, 40 kHz to 100 kHz
The D/A Series include a remote control interface compatible with all standard broadcast transmitter remote control systems.
*D/A Series performance is specified using 710A digital stereo generator at rated power output into a 50-ohm resistive load. Since measurement techniques vary, care should be observed in comparing specifications of different manufacturers. QEI maintains an ongoing program of research and development to insure the finest product performance and quality. All specifications are subject to change without notice.