Company Introduction
Dexter & Co is working with development, procurement and production projects for consumer electronic companies. We have primary focus on projects in the audio sector of consumer electronics. We do projects from concept to production, this includes circuit development, PCB layout design, embedded software development, mechanical design, prototype manufacture, parts procurement, logistics, OEM production, test and quality control.

Texas Instruments PurePath Digital Devices
Our speciality are design and production of products using digital amplifier devices from Texas Instruments. These devices are the best digital amplifiers with digital input on the market. Most digital amplifier devices on the market now are using analog input, this is due to the more traditional Class-D technology used and the possibility of feedback. The PurePath Digital devices with digital input uses a new and patented technology originally developed by danish company Toccata Technology. This technology is still under development by Texas Instruments Denmark.

The PurePath Digital solution has many advantages - e.g. the possibility for digital filters and delay which can be very difficult to make with analog circuits. These extra audio processing possibilities enables products with sound quality better than traditional products in same price range. Another special feature is the amplifier power supply can be used as volume control by adjusting the voltage on the power output stage. This enables very low system noise level - not seen before in consumer audio products. This also help with EMC and EMI concerns.

A DSP is used in all surround-sound products for decoding the data from a DVD or Blue-ray disc. The digital amplifier have advantages in this system because many DSPs are digital and therefore can interface directly so A-to-D and D-to-A converters is not needed.

The True Digital Amplifier
As the headline says all parts of the amplifier is digital - but a analog signal is still needed for the speakers so the last stage of the amplifier is a LC filter that converts the digital signal to analog. The rest of the system is digital - in different formats. A true digital amplifier system could consist of the following stages:

Inputs, e.g. S/PDIF
Power Stages

Digital inputs are usual in S/PDIF format - the S/PDIF receiver device converts the signal to PCM (pulse-code-modulated) format. PCM signal can be re-sampled to another frequency - a CD-player uses 44.1kHz, this can be up-sampled to 192kHz which is used in many high-end audio products. After this the PCM signal is send to the digital modulator. Here it is converted into PWM (pulse-width-modulated) format which is the essential format for digital amplifiers. It is the PCM-PWM modulator that is special for a true digital amplifier. After this the signal is ready for amplification, this is done by a power stage with MOSFETs. The power stage has build-in current, short and temperature protection. The LC-filter is put after the power stage and here after this signal is analog and ready for the speakers. A analog-to-digital converter is added if analog inputs is needed for the system.

Read more about the technology and our small TinyAmp S30 digital amplifier at our product site: | SUMOH |

From Idea to Reality - The Project Process
A Project usually has the following stages:
1) Product/Concept specification
2) Development and prototypes are done and tested according to specification
3) Pre-Production, 5-10 units
4) First production, 25-100 units assembly
5) Automatic test of all units
6) Packaging - complete and ready for customers

Good suppliers - an important resource
Dexter & Co have many suppliers that can deliver components, PCB boards, mechanics, packaging material and so on - both in Denmark and abroad. The suppliers are carefully chosen to secure consistent quality. Most of the suppliers are located in the Asia region where prices also are very competitive.

Special Focus: Automated Production Test
Many electronic companies offer test of the product or parts of it. These are usually done manually and this can be a problem if the test isn't done 100% the same for each unit. Dexter & Co can help with this - by setting up a automated test. The primary testing instrument for audio products are a Audio Precision analyzer. The test are simplified by using this, the unit is connected and the test started - when the test is done a test report are made were errors if any are reported. Dexter & Co can test your products or help make a test for your company.

Please do not hesitate contacting us if you think we can help with your projects.

Dexter & Co
Lyskaer 3B
DK2730 Herlev

Email: info@dxco.dk
Phone: +45 20 62 31 92
Fax: +45 32 11 31 92

Other websites
Digital amplifier made for squeezebox products: | SUMOH |
Danish webshop selling streaming audio products: StreamTech