[TenTec] Orion sweep

[Sinisa Hristov]

Mark Erbaugh wrote:


> Has anyone looked into how the sweep is actually done in the Orion hardware.


Signal path is as follows:

  * board A3:
    * first mixer (Q1-Q4)
    * amplifier (Q24)
    * pre-roofing crystal filter (X1, X2)

  * board A4:
    * source follower (Q17)
    * two stage amp with local AGC (Q13, Q14)

  * board A13:
    * main/sub RX selection (D900)
    * AD9200 ADC (U900)  (10 bits, 20 Msps, SNR 57 dB)
    * 32 K x 8 RAM (U902)

  * board A7:
    * XC95288XL CPLD (U3) (also generates ADC/RAM control signals)
    * MC68EZ328 CPU (U1)


Therefore, a burst of samples is acquired into RAM,
and later transferred to main CPU for processing,
subject to CPU loading.


73,

Sinisa  YT1NT, VA3TTN