1. Manuals
  2. Brands
  3. Timewave Manuals
  4. Noise Reduction Machine
  5. DSP-59+
  6. Operating manual

Timewave DSP-59+ Operating Manual

Audio noise reduction filter
Hide thumbs
Table of Contents

Advertisement

Quick Links

DSP-59+
Audio Noise Reduction Filter
Operating Manual
Manual Version 3.1S
Timewave Technology Inc.

Advertisement

Table of Contents
loading
Need help?

Need help?

Do you have a question about the DSP-59+ and is the answer not in the manual?

Questions and answers

Subscribe to Our Youtube Channel

Related Manuals for Timewave DSP-59+

Summary of Contents for Timewave DSP-59+

  • Page 1 DSP-59+ Audio Noise Reduction Filter Operating Manual Manual Version 3.1S Timewave Technology Inc.

  • Page 2: Table Of Contents

    2. Description of Controls and Connectors 3. Specification 4. Installation 5. Operation 6. Troubleshooting 7. Warranty 8. Electromagnetic Interference 9. Schematic Diagram 10. Appendix - Connector Requirements Copyright 1994, 1995 Timewave Technology Inc. St. Paul, MN USA (612) 452-5939 Manual Rev. 3.1, 27 June 1995...

  • Page 3: Introduction To The Dsp-59

    1. Introduction to the DSP-59+ The DSP-59+ is an audio noise filter for amateur radio voice, data and CW operation. The DSP-59+ filters and reduces noise and interference to improve radio reception. The DSP-59+ uses digital signal processing technology to implement algorithms that perform four basic functions: 1) Random noise reduction, 2) Adaptive multi-tone notch filtering (Tone noise reduction), 3) Bandpass/Highpass/Lowpass filtering, and 4) RTTY remodulation.
  • Page 4 optional CW center frequencies may be internally programmed for older Collins KWM-2 and S-Line equipment. The DSP-59+ also has 12 RTTY, AMTOR, PACTOR, G-TOR and HF packet bandpass filters centered at 2210 Hz. One of five optional center frequencies may be internally programmed for other common operating modes such as European standards or 1600- 1800 Hz.

  • Page 5: Description Of Controls And Connectors

    2. Quick Description of Controls and Connectors (See Section 5, Operation for complete details) Front Panel 1. Overload LED Red LED indicates too high signal level into DSP-59+. 2. Normal Yellow LED indicates normal signal level into DSP-59+. 3. Headphone Jack Stereo headphone jack for 1/8”...

  • Page 6: Specification

    3. Specifications AUDIO INPUT Impedance 2 K ohms or 22 ohms, jumper selectable AUDIO OUTPUT Speaker output power 1.6 watts into 8 ohms at 13.8 VDC 2.5 watts into 4 ohms at 13.8 VDC Line output -6 dB, referenced to input level, into 10K ohms. Not controlled by gain control Distortion less than 1% at rated output NOISE REDUCTION FILTERS...
  • Page 7 VOICE FILTERS Highpass Corner freq. = 200 to 1600 Hz., 60 dB at 180 hz. FIR Linear 18 msec max 100 Hz. steps. outside the passband phase for any combination of highpass & lowpass Lowpass Corner Freq. = 1700 to 3400 Hz., 60 dB.

  • Page 8: Installation

    Shielded coaxial cables with RCA phono connectors should be used to minimize the possibility of RF interference to the DSP-59+. Timewave recommends coaxial video cables with metal adapters to match the connectors on transceivers and speakers. The center pin on the DSP-59+ audio input connector must not be connected to the transceiver speaker ground.
  • Page 9 Audio Input The audio input of the DSP-59+ is an RCA phono connector on the rear panel of the DSP-59+. Matching the output level of the radio to the input level of the DSP-59+ is necessary to take maximum advantage of the wide dynamic range of the DSP-59+. The best way to make these levels match is to use an adjustable audio output of the radio (typically the speaker output) as the input to the DSP-59+.

  • Page 10: Operation

    Use the PTTI bypass in the voice mode to prevent unwanted transmit audio from the transceiver from causing audible interference. Many transceivers do not mute their audio outputs completely during transmit. The 36 dB extra gain from the DSP-59+ with the AGC on makes the incompletely muted transmit audio audible and may even cause oscillation by acoustic feedback from the speaker to the microphone.
  • Page 11 Noise Reduction and Heterodyne Elimination To activate heterodyne/tone elimination and random noise reduction, depress the push-buttons marked "NRt" and "NRr", respectively. Tone elimination , random noise reduction and highpass/lowpass filtering can operate simultaneously or independently. Just depress the desired combinations of push-buttons. One highpass/lowpass filter combination is always active in the highpass/lowpass mode, so set the filters for the widest bandwidth for the best frequency response.
  • Page 12 Wideband Data Operating Hint The DSP-59+ can simulate almost any filter necessary for wideband signals such as wide shift RTTY. If you know the upper and lower audio frequency limits of the signal you are using, simply set the Highpass and Lowpass filters to pass those frequencies. The linear phase response and steep skirts of DSP-59+ will help reject QRM and improve S/N ratio.
  • Page 13 CW Bypass Mode Depressing the Bypass push-button places the DSP-59+ into a bypass mode. In this mode, a relay connects the audio input jack of the DSP-59+ directly to the speaker and headphone output jacks. The relay also connects the audio input jack of the DSP-59+ to the line output jack via a 6 dB attenuator.
  • Page 14 TOR. Unfortunately, some data converters use 200 Hz. shift for RTTY, which adds to the problem of optimally filtering data signals. Center Frequency The center frequency of a FSK signal is independent of the frequency shift or the baud rate. In the audio spectrum, either before an AFSK signal modulates a RF signal or after the RF FSK signal is demodulated, there are several common center frequencies.
  • Page 15 The mark-space frequencies of the modem, receiver and DSP-59+ must match. Default mark-space frequency shifts and center frequencies vary among modem and radio manufacturers, and in different parts of the world. Some modems have default HF Packet mark-space center frequencies different from their RTTY, AMTOR, and PACTOR mark- space center frequencies.
  • Page 16 Data Marker Tones To generate a pair of marker tones for data, set the Center Freq control to 2.21k or Option (red lettering). Set Bandwidth control to 100-150 for 170 Hz. shift or 400-600 for 200 Hz. shift. Depress the Tone (or Marker) push-button to generate two continuous tones at the mark- space frequencies center around the selected center frequency.
  • Page 17 Back Panel Jumper Table Internal Jumper (JH1) Function Setting Audio Input Resistance 22 ohms Audio Input Resistance 2k ohms Voice Noise Reduction Least Aggressive Aggressiveness (NRr) Voice Noise Reduction Less Aggressive Aggressiveness (NRr) Voice Noise Reduction Normal Aggressiveness (NRr) Voice Noise Reduction Most Aggressive Aggressiveness (NRr) reserved...

  • Page 18: Troubleshooting

    6. Troubleshooting SELF-TEST The DSP-59+ has a complete self-test feature that verifies proper hardware and firmware operation. The test has three different parts: 1. Push-To-Talk (PTT) input test. 2. Audio circuitry test 3. Front panel switch test PTT Input Test Connect the DSP-59+ power input jack to a 12-16 VDC @ 1 Amp.
  • Page 19 Connect the DSP-59+ power input jack to a 12-16 VDC @ 1 Amp. power supply. Connect a 4 - 8 ohm speaker to the speaker output jack. Alternatively, connect stereo headphones to the front panel headphone jack. Place all the front panel push-button switches in the out position and rotate both rotary switches to the six o'clock position.

  • Page 20: Warranty

    Timewave Technology Inc. products carry the following warranty: Timewave hardware products are warranted against defects in materials and workmanship. If Timewave receives notice of such defects during the warranty period, Timewave shall, at its option, either repair or replace hardware products which prove to be defective.

  • Page 21: Electromagnetic Interference

    - Connect the equipment into an outlet on a circuit different from that which the receiver is connected. - Consult the dealer or an experienced radio/TV technician. 9. Schematic Diagrams The schematic diagrams in this manual may differ slightly from any particular DSP-59+. Timewave reserves the right to make changes in the DSP-59+ at any time.
  • Page 25 APPENDIX Read before attempting to connect your filter. Wiring information for your Timewave Audio Noise Reduction Filter model DSP-59+ This information is to help you determine which connectors you need for your receiver or transceiver. Connector requirements vary widely. Check your radio owner’s manual for exact details.

Table of Contents