Monday, April 6, 2020

China DSP Radios


Radios made in China are now almost DSP (Digital Signal Processing) Radios.




















DEGEN Model DE321. This is a very good design and good quality. The price is reasonable as FM/AM/SM 3 band radio. I have not opened it yet. I tried but I thought it would be difficult to re-assemble it once open it. The operation manual says <using  SILICON LAB DSP chip>.


























FM/AM Pocket Radio

Front













Side













The design is not particularly good but good enough - large letters (good for senior radio fans) the surface texture is good for handling. The slide switch has three positions - AM - FM - ST-Bass (Stereo Bass). ST-Bass sound is good when I use a reasonably good ear phone,

Inside



















Only one IC found. Tuning is made by a potentiometer. Seems no coils except big one (AM antenna). The model does not say but this is a DSP radio. So DSP radio is not special any more.

This IC does almost every thing (Radio-on-a-chip). It was difficult to detect the name (part number) shown on the surface. By using a magnifying glass and LED light with an appropriate angle I found seemingly <KT0932> from KT Micro. I found data sheet <KT932M> but not <KT0932>. However KT Micro site introduces <KT0932> as follows:

 "
Radio-on-a-Chip™

The KT0932 is KT Micro’s latest generation of proprietary fully integrated AM/FM receiver chip supporting mechanical tuning without MCU. The new features include improved tuning feel, new ST and Tuning light signal, improved EMI/EMC, improved FM stereo separation and improved flatness of sensitivity.

Thanks to its advanced architecture, KT0932 offers an excellent user listening experience with high sensitivity, high signal-to-noise ratio, low distortion and low sensitivity to interference.

KT0932 provides direct and simple interface to support mechanical tuning. A pre-programmed low cost EEPROM can be used to configure the radio settings to differentiate product designs and accommodate standards in various regions. No external MCU is required.

Thanks to its high integration level and efficient user interface design, KT0932 lowers the system cost, simplifies design and improves product reliability and manufacturability. KT0932 can operate with two AAA batteries, making it ideal for low-power portable radio.
Single-chip AM/FM radio solution
      Built-in MCU
      Support analog mechanical tuning
Worldwide FM/AM band support
      Maximum two FM bands with configurable frequency range within 32MHz-110MHz
      Maximum two AM bands with configurable frequency range within 500KHz -1750KHz
High Sensitivity
      1.6uVEMF for FM
      16uVEMF for AM
High Fidelity
      SNR (FM/AM): 58dB/55dB(without weighting filter)
      THD: 0.3%
Low Supply Current
      29mA (operating)    
Integrated stereo indicator
      Programmable sensitivity and hysteresis threshold
Integrated tuning indicator
      Programmable sensitivity and hysteresis threshold
Low supply voltage
      2.1V to 3.6V, can be supplied with 2 AAA batteries
Integrated low power crystal oscillator
      Support 32.768KHz and 38KHz crystal
Arbitrary reference clock supported
       From 30KHz to 40MHz with 1Hz step
Small form factor SSOP20L package

"

I found AM/FM/SW Radio IC KT0936M in Kaide Radio KK-2005 New model (refer to the blog "China made SW radios review - 2").


ACT