Pity you did not e-mail me before you shipped your Quadra off to the Yaesu service centre!

You may wish to join the Quadra Yahoo! Group:

http://groups.yahoo.com/group/YAESUQUADRA/

73, Adam VA7OJ/AB4OJ

Concerns have been expressed that various Digital Mode software packages cannot key the transmitter in the Icom IC-7200 and IC-7600 via the USB "B" port.

The CI-V commands for T/R switching are as follows:

1C 00 00 Transceiver condition RX

1C 00 01 Transceiver condition TX

It is strongly recommended that all amateur radio software developers incorporate these commands in their Icom radio interface layer.

73, Adam VA7OJ/AB4OJ

Hi Tanaka-san,

Sorry - my e-mail address is farson@shaw.ca

73, Adam VA7OJ/AB4OJ

Hi Tanaka-san,

I would like a copy of the VL-1000 service manual as well. Could you send it to me in a Zip file?

Thanks & 73, Adam VA7OJ/AB4OJ

Hi,

From the service manual, it looks as if you will need to remove the enclosure containing the RF and Filter Units, and the metal plate on which the Logic-B Unit is mounted.

The last step before extracting the PLL A/B units (via the side opening) is to unplug the connectors from the Logic-B Unit.

As you start the disassembly procedure, the sequence should become clearer.

Best 73,
Adam, VA7OJ/AB4OJ

Hi Ted,

Outboard audio DSP "boxes" were an adjunct to HF receivers using classical analogue filters. They provided noise reduction, a notch filter and audio filtering. These devices were post-AGC, and could not eliminate undesired signals prior to demodulation and AGC derivation. An outboard audio DSP unit is still a useful accessory for an older HF rig.

Advances in DSP, ADC (analogue/digital converter) and DAC (digital/analogue converter) chipsets have made possible the development of DSP-based HF transceivers in which the DSP performs all functions, including IF filtering, modulation and demodulation. These implementations have eliminated the need for analogue filters.

There is an extensive discussion of DSP radio design on the following links:

http://www.qsl.net/ab4oj/icom/ic756pro_notes.html

http://www.qsl.net/ab4oj/icom/pro_dsp.html

http://www.qsl.net/ab4oj/icom/dspfilter.html


Best 73, Adam, VA7OJ/AB4OJ

http://www.qsl.net/ab4oj/

"We have learned" that ICOM has recently concluded a licensing agreement with the well known maker of "Ultra-high-end" Mil-spec radio gear, Rohde & Schwarz of Munich, to use R&S circuitry in certain ICOM radios (particularly in the front end). This supports the probable targeted market for the "IC-785", Mil/Gov/Commercial; it would also make the radio highly attractive in the E.U. The "IC-785" will probably list in the $6K price bracket, comparable to the venerable IC-781. Even at that price level, it is likely to be pack-leader by a country mile, when compared to its ham-market competitors.

Rohde & Schwarz and Racal are the main European competitors to Rockwell-Collins and RF-Harris.

73, Adam, VA7OJ/AB4OJ

http://www.qsl.net/ab4oj/

Hi John,

To those who would rewrite Icom's DSP firmware, I say "Rotsa ruck" getting their hands on the source code! We're talking about the manufacturer's Crown Jewels.

Cheers, 73,
Adam VA7OJ/AB4OJ

Hi Matt,

Just to expand on your posting:

There is a lot of material on these topics on my "Icom" page.
http://www.qsl.net/ab4oj/icom/icom.html

The following links are relevant to this discussion:

Basic Concept of Icom IF-DSP

George, W5YR's articles on occupied bandwidth, the Monitor and Filters & DSP.

IC-756Pro User Reviews (yours and mine)

There is no balanced modulator in a DSB-based SSB transceiver. The speech amplifier drives the analogue/digital converter (ADC), which digitises the transmit audio. The DSP processes the resulting bitstream. The digital/analogue converter (DAC) converts the processed bitstream to an analogue IF signal, which is up-converted and amplified for transmission. The exact reverse process takes place in the receiver.

The DSP generates SSB by mathematically modelling a phasing-type SSB exciter.

DSP is not only here to stay; it allows radio designers to achieve levels of performance and functionality unattainable with analogue designs. With the advent of faster and cheaper ADC, DAC and DSP chipsets, DSP radio architectures have also become significantly more cost-effective to implement than analogue solutions offering the end-user far less in terms of performance/capability.

Best 73,
Adam, VA7OJ/AB4OJ
http://www.qsl.net/ab4oj/

Check out the Icom FAQ site: http://www.qsl.net/icom/