The Type COS-1 Costas/squaring loop provides a training platform in the design and operation of the classical textbook implementation of a Costas and squaring loop for the demodulation of Bi-phase shift keying (BPSK) signals without a coherent carrier. The Type COS-1 system can be configured as a Costas loop or as a squaring carrier-regenerating loop. Either loop type offers adjustable I and Q-Arm lowpass filter bandwidths from 758Hz ~ 284kHz and is complete with a loop acquisition sweep generator to aid in loop lock. The acquisition sweep generator sweep rate is selectable, and the sweep can be disabled, if desired. The sweep is automatically disabled once acquisition is reached and turns on if loop lock is lost. The Type COS-1 possesses an on-board RMS power detector for accurate signal and noise power level settings. The Type COS-1 has built-in coherent lock detectors for both the Costas and squaring loop.
The loop lock threshold is fully adjustable and a loop lock indication is provided. The Costas loop locks onto the BPSK signal for demodulation and offers the choice of using an in-phase channel limiter. The squaring loop regenerates the carrier and the carrier phase can be optimally adjusted to take into account the squaring operation bandpass filter phase offset (delay).
Noise can be introduced into the Costas loop to study the lock and acquisition performance as a function of the SNR. The Type COS-1 Costas/squaring loop interfaces with the Type MOD-1 Signal Modulator whereby recovered 8-bit PCM or CVSD digital audio can be looped back for performance tests under varying SNR. The Bit Error Ratio (BER) can be measured by connecting the Type COS-1 platform to the Type BER-1 BER Measurement board and additive noise introduced into the system by connecting the Type NS-1 Noise Source. Together, these systems form a platform for the performance analysis of BPSK demodulation using these loops. Operation requires +/-12 VDC @ 500mA, maximum, and power is supplied from the Type MOD-1 Signal Modulator. Power inputs are polarity protected.
The Type COS-1 Costas/squaring loop includes:
- Technical Manual that covers Configuration, Operation, General Theory, Block Diagrams, Schematic Diagrams. 111 pages, 50 Figures, 11 Tables. Parts List.
- One, 3-foot length RG-58/BNC 50-ohm cable
- One, 3-foot power cable for connection to Type MOD-1 Signal Modulator
- 36, 2-pin configuration jumpers
- Type COS-1 board outline is (width x depth) 10" x 10" (254.0 x 254.0mm)