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Inside a WorldSpace satellite radio receiver

WorldSpace is no longer operational. But I had a receiver lying around from when it was active. I opened it up and here is what I found in it:

Antenna Unit

Front Panel

Inside of the front panel

Main Board

Mainboard with the various sections marked out

STA001 – RF Frontend for Digital Radio
  • Single chip receiver for satellite digital transmission
  • Superheterodyne receiver with IF output
  • High input intercept point, low Mixer noise
  • 54db IF VGA gain range
  • Adjustable RF gain
  • Adjustable IF gain 
  • Integrated RF VCO
  • Integrated IF VCO
  • Integrated synthesizer
  • I2C bus compatible programming Interface
  • Unregulated 2.7 volts to 3.3 volts voltage Supply
  • Low cost external components
Block Diagram of STA001 – RF Frontend for Digital Radio

STA002 – Starman Channel Decoder
  • Front end interface
    • IF input carrier frequency: f = 1.84 MHz
    • Single internal 6 bit A/D converter
    • QPSK demodulation
    • Input symbol frequency: Fs = 1.84 Msymbols/s
    • Digital Nyquist root filter:
      • Roll-off value of 0.4
    • Digital carrier loop:
      • On-chip quadrature demodulator and tracking loop
    • lock detector
    • C/N indicator
    • Digital timing recovery:
      • Internal timing error evaluation, filter and correction
    • Digital AGC:
      • Internal signal power estimation and filter
      • Output control signal for AGC (1 bit PWM)
  • Forward error correction
    • Inner decoder
      • Viterbi soft decoder for convolutional codes, constraint length M=7, Rate 1/2
    • Deinterleaver block
    • Outer decoder
      • Reed-Solomon decoder for 32 parity bytes; correction of up to 16 byte errors
      • Block lengths: 255
      • Energy dispersal descrambler
  • Back end Interface
    • Broadcast Channel selection
    • Audio Service Component selection to MPEG decoder
    • Service Component selection
  • Control
    • I2C serial Bus control interface
  • Decryption
    • WES Scheme
Block Diagram of STA002 – Starman Channel Decoder

STA003T – MPEG 2.5 Layer III Audio Decoder
  • Single chip MPEG2 layer 3 decoder
  • Supporting
    •  All features specified for Layer III in ISO/IEC 11172-3 (MPEG 1 Audio) except 44.1KHz Audio
    • All features specified for Layer III 2 channels in ISO/IEC13818-3.2 (MPEG 2 Audio) except 22.05KHz Audio
    • Lower sampling frequencies syntax extension, (not specified by ISO) called MPEG 2.5 except 11.025KHz Audio
  • Decodes layer III stereo channels, dual channel, single channel (mono)
  • Supporting the MPEG 1 & 2 sampling frequencies and the extension to MPEG 2.5:
    48, 32, 24, 16, 12, 8 kHz
  • Accepts MPEG 2.5 layer III elementary compressed bitstream with data rate from 8 kbit/s up to 128 kbit/s
  • Digital volume control
  • Digital bass & treble control
  • Serial bitstream input interface
  • Ancillary data extraction via I2C interface.
  • Serial PCM output interface (I2S and other formats)
  • PLL for internal clock and for output PCM clock generation
  • Low power data elaboration for power consumption optimisation
  • CRC check and synchronisation error detection with software indicators
  • I2C control bus
  • Low power 3.3 volts CMOS technology
  • 14.72 MHz external input clock or built-in crystal oscillator
    Block Diagram of STA003T – MPEG 2.5 Layer III Audio Decoder

PT6524 – LCD Driver IC
  • CMOS Technology 
  • Up to 4 Common and 51 Segment Drivers 
  • Up to 204 LCD Segments 
  • Up to 12 General Purpose Output Ports 
  • 1/4 Duty – 1/2 Bias or 1/4 Duty – 1/3 Bias Drive Technique 
  • No Decoder Intervention Necessary to Display the Data 
  • Power Saving Mode provided 
  • RC Oscillation Circuit
Block Diagram of PT6524 – LCD Driver IC

ST72F321 – Microcontroller
  • Memories
    • 32K to 60K dual voltage High Density Flash (HDFlash) or ROM with read-out protection capability. In-Application Programming and In-Circuit Programming for HDFlash devices
    • 1K to 2K RAM
    • HDFlash endurance: 100 cycles, data retention: 20 years at 55°C
  • Clock, Reset And Supply Management
    • Enhanced low voltage supervisor (LVD) for main supply and auxiliary voltage detector (AVD) with interrupt capability
    • Clock sources: crystal/ceramic resonator oscillators, internal RC oscillator, clock security system and bypass for external clock
    • PLL for 2x frequency multiplication
    • Four Power Saving Modes: Halt, Active-Halt, Wait and Slow
  • Interrupt Management
    • Nested interrupt controller
    • 14 interrupt vectors plus TRAP and RESET
    • Top Level Interrupt (TLI) pin on 64-pin devices
    • 15 external interrupt lines (on 4 vectors)
  • Up to 48 I/O Ports
    • 48/32 multifunctional bidirectional I/O lines
    • 34/22 alternate function lines
    • 16/12 high sink outputs
  • 5 Timers
    • Main Clock Controller with: Real time base,
    • Beep and Clock-out capabilities
    • Configurable watchdog timer
    • Two 16-bit timers with: 2 input captures, 2 output compares, external clock input on one timer,  PWM and pulse generator modes
    • 8-bit PWM Auto-reload timer with: 2 input captures, 4 PWM outputs, output compare and time base interrupt, external clock with event detector
  • 3 Communications Interfaces
    • SPI synchronous serial interface
    • SCI asynchronous serial interface 
    • I2C multimaster interface
  • 1 Analog peripherals
    • 10-bit ADC with up to 16 input ports
  • Instruction Set
    • 8-bit Data Manipulation
    • 63 Basic Instructions
    • 17 main Addressing Modes
    • 8 x 8 Unsigned Multiply Instruction
  • Development Tools
    • Full hardware/software development package
    • In-Circuit Testing capability
Block Diagram of ST72F321 - Microcontroller


  1. have you found a way to reprogram it? ive been trying to find anything related to it on the web but have failed. on the normal broadcast you get yazmi audio.....which is playing old maestro channel tunes.....any ideas?~?

  2. Hi,
    I broke my WorldSpace opening it :P. So of course it won't work any more. Meanwhile try the Saregama Worlspace app for Android: it seems to have the Farishta Channel too!!

  3. dear Anurag
    I also own a tongshi damb-r receiver, that i dismantle, i found inside a tuner labelled TDW-A (200509 05)
    Have you got information about this tuner, or could you tell me if yours device features a usb port for linking to a pc computer in order to receive data.
    FYI Worldspace satellite still operational with a US company called omni-sat
    Waiting for your reply.

  4. Hi, I am not aware of the TDW part number. My device does not have a USB Port

  5. Hai all ...i want used world space satellite radio and antenna (or antenna)


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