Review of Radio Shack Accurian 12-1686 HD receiver by Bob Foxworth - in 4 parts
begin part 4 of 4 The receiver also delays anything it handles (analog or digital, AM or FM) by about 100 ms behind the signal as heard on an ordinary receiver. If a previously heard -2 is still cached in the receiver, the HD unlocks, and the -2 is tuned, silence results. There were a couple of episodes where the tuning was changed from a HD to a non-HD and a couple more buttons had to be pressed to get the sound back. Aux In. The fifth input option (2 AM, 2 FM and Aux) lets you feed the output of another sound device into the set. This is very useful to me. I have several small digital recorders and can feed the headset output through the set, with good results. Take care to not overdrive the input, but a decent headset level from the recorder should be optimum. Insides. Here is a posting from the Broadcast list digest which is quite interesting. As I may yet return the set, I am not about to open it up. --------------------- Message: 20 Date: Sat, 2 Dec 2006 19:41:19 -0600 From: "stanleybadams" <[EMAIL PROTECTED]> Subject: [BC] Accurian Insides To: <[EMAIL PROTECTED]> Message-ID: <[EMAIL PROTECTED]> Content-Type: text/plain; charset="us-ascii" I was tooling around the internet looking for reviews and information on the Accurian, as I received mine this week but have not turned it on yet. Here is what someone posted on a web site (www.avs.forum.com) by the name of Eric. So I am giving credit where credit is due I finally had the courage to open up the radio and look inside (Hint: some screws are hidden under the speaker grilles). There is a Samsung module that plugs into a PCB named "Table-Top Version 2.2". The Main PCB contains the Power Supply, Amplifier, and connectors for the display, speakers, keypad, etc. The Samsung HDRMDVM0101 module contains the heart of the radio. The module has a 20 pin and a 50 pin connector to interface to the Main PCB. The module also has a JTAG connector for the ATMEL Processor. ICs on the module include: ATMEL Mega128L Low Power AVR RISC Processor with 128K Flash TI TMS320DRI350AZTS5 DSP for HD Radio Baseband and Analog Decoding TI DRI8201 Intergrated AFE Spansion S29GL032M90TFIR4 3.3V 32Mb Flash x8/x16 Bottom Boot Sector ESMT M12L128324A 3.3V 4MBx32 SDRam 1803A 24bit 96K Stereo Audio ADC 1782 24bit 96K Stereo Audio DAC LM833 Dual Op Amp This is a Software Defined Radio where the AM or FM signal is converted to a 10.7 MHz IF and then digitized. The digitized IF gets downconverted and fed to the DSP where either AM, FM or HD signals are decoded and sent to the Stereo Audio DAC. It appears even the Aux Input is digitized. Several companies offer modules based on the HD reference design so I would not be surprised if most HD radios use the same scheme. Plug a module into a I/O board and put a custom user interface/ configuration in flash. Obviously, the speakers can be replaced or the audio fed into a stereo system, but as you see they are modules such as this Samsung, or what TI or others would build. It is a single unit radio that has the real guts in the decoders, not in the RF section. Somebody ought to build a good American made copy of this thing, don't you think? Stanley Adams Memphis ------------------------ This tends to confirm my own thoughts about the RF behavior. PS a JTAG is a test point to allow diagnostic and interfacing on a otherwise self- contained module. end of review. 20061203. by Bob Foxworth _______________________________________________ IRCA mailing list [email protected] http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: [email protected]
