Specifications of Deajeon Correlator

Specifications of Deajeon Correlator
Item Description
Observation Array Constitution
  • Number of Stations
  • Number of Inputs for a station
  • Sub-array Constitution
  • Total number of Correlation
  • (max.) 16 stations
  • (max.) 4 inputs
  • 4+12 stations / 8+8 stations
  • (max.) (16 Auto
  • + 120 Cross-) × 4 sets
Observation Requirements
  • Observation Frequency
  • Largest Baseline Length
  • Maximum Baseline Velocity
  • Frequency Resolution
  • Dual Polarization
  • P-cal Detection
  • Maximum Data Output Rate
  • (space VLBI)45GHz, (Others)130/86/43/22GHz
  • ± 36,000 km (±0.12 sec)
  • 7.5 km/sec
  • 53.3m/sec (for 22GHz Observation)
  • Yes, for only 8 stations at once
  • Yes
  • 1.4 GBytes/sec
Input Data Profiles
  • Digitization
  • Quantization Levels
  • Interface
  • PDATA Acceptance
  • Data Rate
  • Input Format
  • 1024 Msamples/sec × 2 bits/sample
  • 4 levels as "00" < "01" < "10" < "11"
  • VSI-H (32parallels data, 1PPS, VALID, PDATA)
  • As "format A" of ADS-1000
  • 2Gbps / 1Gbps
  • Wide Band Mode (1Gsps x 2bits)
  • Narrow Band Mode (1Gbps/512Mbps Multi Data Streams)
  • Narrow Band Mode2(2Gbps Multi Data Streams)
Input Data Control
  • Rate up Data Acceptance
  • Stream Selection & Multiplexing
  • Yes, Double rate(form 1Gbps) / Quadruple rate(from 512Mbps)
  • Yes
Delay Compensation & Fringe tracking
  • Delay Prediction Parameters
  • Delay Compensation Period
  • Fringe phase quantization
  • Fringe phase applying range
  • Word length of Fringe tracking
  • τg , τg’, τg” and τg’’’ (for 1.024 sec)
  • According to FFT segment border
  • 2π/16 radian
  • every 1samples
  • 16bits, 2's complement
Special Analysis
  • FFT points
  • Word length
  • Window modulation
  • Delay residual(△w) compensation
  • Scaling
  • Cancellation DC-offset
  • Frequency Offset Addition
  • Re-quantization
  • 256k / 128k / 64k / 32k / 16k / 8k points ("k" means "×1,024")
  • Fixed point 20+20 bits (real + imaginary)
  • Yes, 4 kinds as "Rectangular" / "Hamming" / "Hanning" / "Blackman"
  • Yes
  • Yes
  • Yes
  • Yes
  • Fixed point 8+8 bits (real + imaginary) : The Output are only USB or LSB
Correlation & Accumulation
  • Word length of Correlation
  • Station Data Switching
  • Word length of Accumulation
  • Integration Period
  • Frequency binning / Frequency binning setting points
  • Points of Correlation Output Data
  • Correlation Output Data Interface
  • Fixed point (8+8) bits → (15+15) bits
  • Yes
  • Fixed point (32+32) bits (real + imaginary)
  • 25.6msec/51.2ms/102.4ms
  • 10.24sec(102.4ms unit)
  • Yes, 1 / 2 / 4 / 8 / 16 / 32 / 64 / 128 / 256 channels bin.
  • Yes, (for each 512-points of output)
  • 8,192-points(for each correlation). Each points are result of binning
Control Interface 10Gbits Ether × 4 ports, TCP/IP, Based on VSI-S

Correlation Mode

Correlation Mode Data Constitution Current Possibility
Wide Band Mode 1Gsps x 2-bits x 4-streams/station
  • W1: 4 independent inputs(4Fx1P)
  • W2: 1 polarization pair+2 independent inputs (1Fx2P+2Fx1P)
  • W3: 2 polarization pairs(2Fx2P)
 W1 is available.
Narrow Band Mode1 1Gbps or 512Mbps Multi Data Streams/Station
  • Rate up to 2Gbps 10 patterns are as follows :
    • C1 : 256MHz BW x 1-stream
    • C2 : 128MHz BW x 2-streams
    • C3 : 64MHz BW x 4-streams
    • C4 : 32MHz BW x 8-streams
    • C5 : 16MHz BW x 16-streams
    • C6 : 8MHz BW x 16-streams
    • C7 : 64MHz BW x 2-streams + 128MHz BW x 1-stream
    • C8 : 32MHz BW x 2-streams + 64MHz BW x 1-stream + 128MHz BW x 1-stream
    • C9 : 32MHz BW x 4-streams + 128MHz BW x 1-stream
    • C10 : 16MHz BW x 2-streams + 32MHz BW x 3-streams + 128MHz BW x 1-stream
    		 C1/C2/C3/C4/C5 are available.
    Narrow Band Mode2 2Gbps Multi Data Streams/station
  • Same as Narrow Band Mode
  • Bandwidth is double
  • C6 is excluded
    		•  Not Yet