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Discontinued Product
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Reduce noise and interference - Adaptive noise filter for Voice and CW Eliminate heterodynes - Automatic multiple tone noise filter Sharp Speech, CW and Data filters - 555 Linear phase FIR filters - 25 Hz. - 600 Hz. adjustable bandwidth for CW & Data - 200Hz. - 3.4 kHz. adjustable Lowpass & Highpass - RTTY, AMTOR, PACTOR, HF-Packet and G-TOR Built-in Self-Test & Audio Generator |
The noise reduction functions of the DSP-59+ 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-59+ 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.
SSB signals often have a high signal-to-noise ratio but have interference from other signals that overlap the desired signal. The steep skirts of the highpass and lowpass filters allow the interference to be eliminated with minimal impact on the desired signal. The 30 selectable highpass and lowpass filters also allow enhanced filtering for other modes such as SSTV, wideshift RTTY or facsimile. Highpass filters range from 200 to 1600 Hz and lowpass filters range from 1700 to 3400 Hz.
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.
The DSP-59+ is compatible with all amateur radio transceivers and receivers. Simply connect the DSP-59+ between the radio and its speaker or headphones. Connect 12-16 VDC to the DSP-59+ 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 freq. range of selected bandpass filter |
Up to 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 Adaptive noise characteristics |
Adaptive | 5 msec max |
| Function | Frequency range | Attenuation | Type | Delay |
| Highpass | Corner freq. = 200 to 1600 Hz., 100 Hz. steps. |
60 dB at 180 Hz. outside the passband |
FIR Linear phase |
18 msec max for any |
| Lowpass | Corner freq. = 1700 to 3400 Hz. 100 Hz. steps |
60 dB at 180 Hz. outside the passband |
FIR Linear phase |
combination of highpass and lowpass |
| Function | Frequency range | Attenuation | Type | Delay |
| CW Filters | Bandwidth = 25 Hz to 600 Hz, 15 steps. |
60 dB at 50 Hz. outside the passband |
FIR Linear phase |
30 msec max |
| Center freq. = 400 to 1000 Hz., 50 Hz. steps. |
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| Optional Collins KWM-2 & S-Line |
Bandwidth = 25 Hz to 600 Hz Center freq. = 1350, 1500, 1750 Hz. |
55 dB at 75 Hz. outside the passband. |
FIR Linear phase |
18 msec max |
| CW Marker Tone | Sine wave at center freq. of selected CW filter. Sine wave distortion less than 1% |
| Function | Frequency range | Attenuation | Type | Delay |
| RTTY, AMTOR, PACTOR, G-TOR, & HF-Packet |
Bandwidth = 100 Hz. to 600 Hz. Center freq. = 221-0 Hz. plus option of 1700(default), 1360, 1300, 1530 or 2125 Hz. |
40 dB at 60 H. outside the passband |
FIR linera phase |
18 msec max |
| SSTV | 1100-1300 Hz. & 1500-2300 Hz. | 50 dB at 75 Hz. outside the passband |
Composite FIR Linear phase |
18 msec max |
| WEFAX | 1500-2300 Hz. | 55 dB at 75 Hz. outside the passband |
FIR Linear phase |
18 msec max |
| CLOVER | 2000-2500 Hz. | 55 dB at 75 Hz. outside the passband |
FIR Linear phase |
18 msec max |
| FSK Marker Tone | Sine waves at mark-space freq. of selected data filter(170 or 200 Hz.
shift). Sine wave distortion less than 1% |
| Volume / power On-Off | Bandpass center freq. adjust |
| Bypass switch | Bandpass bandwidth adjust |
| AGC switch | Lowpass roll-off freq. adjust |
| Random Noise Reduction switch | Highpass roll-off freq. adjust |
| Tone Noise Reduction switch | Marker Tone switch |
| Bandpass / Highpass / Lowpass 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. |
| Test tones | Single or two-tone. Sine wave at the center freq. of each highpass and
lowpass filter. Sine wave distortion less than 1%. |
| Size | 7.6 in. wide x 8.5 in. deep x 1.9 in. high (193 mm wide x 216 mm deep x 48 mm high) |
| Weight | 2.0 lb. (0.9 Kg.) |
| 12-16 VDC @ 1A |
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