FM Broadcast Exciter Model 675B
QEI advanced technology FM Exciters for outstanding audio performance. The Model 675B continues the tradition of superior performance and reliability set by it's legendary predecessor the venerable Model 675. QEI took this time-proven exciter design and has refined the system to deliver un-compromised performance for today's FM broadcast station.
The Model 675B FM is an "all solid state, on carrier direct FM, phase locked, frequency synthesized exciter", designed to exceed the FCC requirements for use in the FM broadcast band.
The Model 675B exciter may be programmed to operate on any 100 kHz increment in the FM band. 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 Model 675B has superior linearity and does not require any "pre-distortion" networks. Sound for sound the Model 675B will match other FM exciters costing twice as much or more. The FMO is sealed in steel and foam to shield it from stray magnetic fields and eliminate microphonics.Download the
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The Power Amplifier (PA) of the Model 675B is unconditionally stable and will withstand any magnitude or phase of VSWR indefinitely without damage. The Model 675B's power output can be varied from 2 Watts to greater than 20 Watts without oscillation or "break up". The Model 675B is designed with components that are operated conservatively and well within their ratings.
Housed in a rack space saving 3-1/2" self contained package, the Model 675B will fit into virtually all transmitters in use and is the perfect upgrade for older systems.
Complete metering of critical parameters is available at the push of a button. All operational indicators are LED's to eliminate all routine lamp replacement.
RF and audio connections are made by way of back panel connectors. A BNC for composite audio, barrier strip for monaural audio and a Type "N" RF output connector.
Reliability and simplicity of design and operation make the Model 675B FM exciter an outstanding choice for every FM station.
A short list of features:
- Frequency Synthesized
- Phase Locked
- "On Carrier" Direct FM
- Unconditionally Stable Amplifier
- All Solid State
- Ultra Low Distortion, Crosstalk and Noise
- "VSWR Proof"
- Stability +/- 200 Hz (0°C to 50°C)
- Compact 3-1/2" Rack Mount Package
QEI FM exciters, designed and manufactured with pride in the U.S.A.
Technical Specifications
General
Power Output: 2 to 20 Watts
Frequency Range: 87.5 to 108 MHz (other frequencies optional)
RF Load Impedance: 50 ohms
Output Connector: Type "N" Female
VSWR: Operation into any phase or magnitude
RF Harmonic/Spurious: Suppression meets or exceeds all FCC /DOC / CCIR specifictions
Frequency Stability: +/- 200 Hz from 0 degrees C to 50°C
Modulation Capability: Greater than +/- 200 kHz
Pre-Emphasis:
Standard: 75usec (FCC)
Optional: 50usec (CCIR)
Asynchronous AM S/N Ratio (AM Noise): -60 dBc (no FM modulation present)
Synchronous AM S/N Ratio (Incidental AM): -50 dBc with 100 % FM Modulation
Electrical/Mechanical
AC Power requirement: 105-125 / 210-250 VAC 50/60Hz.
Power Consumption: 50 Watts
Ambient Temperature Range:
Operating -15°C to +50°C
Startup 0°C to +50°C
Maximum Humidity: 95% non-condensing
Size: 3.5"H (8.9cm) x 19"W (48.25cm) x 14" D (35.5cm)
Weight: 17 Lbs.
Monaural Performance
Audio Input Impedance: 600 ohm balanced
CMRR:>60 dB
Audio Input Level: +10 dBm nominal for +/-75 kHz deviation at 100 Hz
Audio Frequency Response: +/-0.5 dB, 30 Hz to 15 kHz
Total Harmonic Distortion + Noise: 0.08 % or less at 400 Hz
FM S/N Ratio: 73 dB below +/-75 kHz deviation at 400 Hz, measured in a 20 Hz to 30 kHz bandwidth with 75 usec de- emphasis
Wideband Composite Performance*
Inputs: (1) unbalanced on rear panel, BNC-connector
Input Impedance: 10K ohm , nominal, resistive
Input Level: 3.5 Vp-p nominal, for +/-75 kHz deviation
FM S/N Ratio: 73 dB below +/- 75 kHz deviation at 400 Hz, measured in a 20 Hz to 30 kHz bandwidth with 75 usec de-emphasis
Total Harmonic Distortion + Noise: 0.08 % or less at 400 Hz
Amplitude Response: +/-0.01 dB, 30 Hz to 75 kHz
Phase Response: +/-0.1 degrees from linear phase, 30 Hz to 75 kHz
Stereo Performance*
Modulation Type: True numeric digital stereo generation, digitally generated pilot; no alignment required.
Frequency Response: +/-0.1 dB, 30 Hz to 15 kHz, 75 usec or 50 usec pre-emphasis
Total Harmonic Distortion + Noise: 0.08 % or less at 400 Hz
FM S/N Ratio: 73 dB below +/- 75 kHz deviation at 400 Hz, measured in a 20 Hz to 30 kHz bandwidth with 75 usec de-emphasis
Stereo Separation: >60 dB or better , 30 Hz to 15 kHz
Dynamic Stereo Separation: >60 dB or better, 30 Hz to 15 kHz (normal program material)
Crosstalk:
Linear ...Main to Sub/Sub to Main due to amplitude and phase matching of left and right channels, 30 Hz to 15 kHz, -60 dB below +/-75 kHz deviation.
Non-Linear.......Main to Sub/Sub to Main due to distortion products. -60 dB below +/- 75 kHz deviation
SCA Performance
Subcarrier Inputs: (2) total, unbalanced, BNC connectors
Subcarrier Input Impedance: 10K ohm
Subcarrier Input Level: 1.0 Vp-p , nominal for 10 % injection
Subcarrier Amplitude Response: +/-0.2 dB, 40 kHz to 100 kHz
* Model 675B performance is specified using 710 digital stereo generator at rated exciter power output into a 50 ohm resistive load. Specifications are subject to change without notice. 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.