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Discontinued Product
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Reduce noise and interference - Adaptive noise filter for SSB and AM Eliminate heterodynes - Automatic multiple tone noise filter - AGC (Automatic Gain Control) Sharp Speech, CW and Data filters - Linear phase FIR filters - 1.6, 2.0 and 2.4 kHz. Bandpass - 100, 200 and 500 Hz. Bandpass - RTTY, AMTOR, PACTOR, HF-Packet and G-TOR Built-in Self-Test |
The noise reduction functions of the DSP-9+ operate by examining a characteristic of signals and noise called correlation, and dynamically filtering out the undesired noise. The degree of correlation is relative. Random noise such as white noise or static is uncorrelated. Speech is moderately correlated. Heterodynes and pure tones are highly correlated. The DSP-9+ measures correlation and automatically filters out noise that is outside its correlation thresholds. The amount of noise reduction varies according to the correlation characteristics of the noise. Typical noise reduction ranges from 5 dB to 20 dB for random noise and up to 50 dB for heterodynes.
Narrow band signals like CW and RTTY require bandpass filters with steep skirts and linear phase response. Linear phase response maximizes the usable signaling rate for a given bandwidth and minimizes ringing often heard on other types of extremely sharp filters. The filter skirts on the 195 CW filters are so steep that a signal literally falls off the edge of the passband as you tune through a CW signal. Bandwidths range from 25 Hz to 600 Hz, and center frequencies from 400 to 1000 Hz. The narrow filters are useful for trying to dig out extremely weak signals from the noise and QRM. The wider filters allow easy tuning and listening to multiple CW signals simultaneously. The selectable bandwidths of the 2210 Hz and optional data bandpass filters allow selection of the optimum bandwidth for 170 Hz and 200 Hz shift data signals of various baud rates.
Front panel pushbutton switches enable quick, independent selection of all the functions on the DSP-9+. In the voice mode, the operator can simultaneously select a bandpass filter, the tone notch filter and the random noise reduction filter. This means you can reduce QRN, filter adjacent-channel QRM, and eliminate heterodynes at the same time! In the CW mode, simultaneous selection of both the random noise reduction filter and a bandpass filter reduces background hiss as well as adjacent-channel signals. AGC (Automatic Gain Control) is selectable in all modes to optimize filter performance and listening ease with varying signal levels.
The DSP-9+ is compatible with all amateur radio transceivers and receivers. Simply connect the DSP-9+ between the radio and its speaker or headphones. Connect 12-16 VDC to the DSP-9+ and turn it on!
| Impedance | 2K ohms or 22 Ohms, jumper selectable |
| Output power | 1.6 watts into 8 ohms at 13.8 VDC, 2.5 watts into 4 ohms at 13.8 VDC |
| Line output level | -6 dB, referenced to input level, into 10K ohms. Not controlled by gain control |
| Distortion | less than 1% at rated output |
| Function | Frequency range | Attenuation | Type | Delay |
| Random Noise Reduction | Entire range of selected bandpass filter |
Up ro 20 dB, varies with noise characteristics |
Adaptive | 5 msec max |
| Tone Noise Reduction (multiple automatic notch) |
Entire freq. range of selected bandpass filter |
Up to 50 dB, varies with noise characteristics |
Adaptive | 5 msec max |
| Bandpass - Voice | 300 Hz - 3.4 kHz, 300 Hz - 2.7 kHz and 300 Hz - 2.1 kHz or (jumper selectable) 300 Hz - 2.7 kHz, 300 Hz - 2.3 kHz and 300 Hz - 1.9 kHz |
60 dB at 180 Hz outside the passband |
FIR Linear phase |
10 msec max |
| Function | Frequency range | Attenuation | Type | Delay |
| Bandpass - CW | Bandwidth = 100 Hz, 200 Hz and 500 Hz Center freq. = 400, 500, 600, 800 Hz (select any two by internal jumper, or Collins KWM-2 mode with center freq. = 1350 and 1500 Hz |
60 dB at 50 Hz outside the passband |
FIR Linear phase |
30 msec max |
| Random Noise Reduction |
Entire freq. range of selected bandpass filter |
Up to 20 dB, varies with noise characteristics |
Adaptive | 18 msec max |
| Function | Frequency range | Attenuation | Type | Delay |
| RTTY | Bandwidth=250 Hz. | 55 dB at 50 Hz outside of bandpass |
FIR Linear phase |
18 msec max |
| AMTOR | Bandwidth = 340 Hz | |||
| PACTOR, G-TOR | Bandwidth = 440 Hz | |||
| HF Packet | Bandwidth = 540 Hz | |||
| All Data Modes | Mark - Space freq. pairs = 2125 - 2295, 2110 - 2230, 2025 - 2225, 1615 - 1785, 1600 - 1800, 1430 - 1630, 1275 - 1445, 1260 - 1460, 1215 - 1385, 1200 - 1400 Hz Jumper table in Manual |
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| Volume / Power On-Off | Voice / CW bandpass Bandwidth switches (wide and narrow) |
| Voice / CW / Data Mode switch and LED indicators |
CW center frequency switch (high and low) |
| Bypass switch | Overload LED |
| AGC switch | Normal LED |
| Random Noise Reduction switch | RTTY, AMTOR, PACTOR, and HF Packet switches |
| Tone Noise Reduction switch | RTTY Remodulator switch |
| Audio Input | Phono jack - RCA style |
| Speaker Audio Output | Phono jack - RCA style |
| Line Audio Output | Phono jack - RCA style |
| PTT Input | Phono jack - RCA style |
| Power In | 5.5 mm / 2.1 mm power jack (center positive) |
| A-D/D-A Converter | 16 bit linear, sigma-delta conversion |
| Signal Processor | 16 bit, 77ns Analog Devices ADSP-2105 |
| Self-test | Self-test for circuitry, switches, and PTT input. User initiated from front panel. |
| Size | 5.9 in. wide x 6.7 in. deep x 1.9 in. high (150 mm wide x 170 mm deep x 48 mm high) |
| Weight | 2.0 lb. (0.9 Kg.) |
| 12-16 VDC @ 1A |
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