The radio local distribution system (RLDS) has been proposed to transmit various business information signals. The proposed RLDS uses a 26 GHz band and time division multiple access (TDMA). The main features of the RLDS are the use of radio equipment containing the microwave integrated circuit (MIC) and the adoption of the demand-assigned TDMA (DA/TDMA) technique. The MIC is more suitable than conventional waveguide circuits for mass production because its components are miniaturized. The DA/TDMA system, operating in a fully variable demand-assignment mode, uses simple control systems with a low bit rate. As a result, the RLDS can serve a local distribution system of high-speed digital communications both expeditiously and economically.

A theoretical analysis is presented for a multi-hop relay system composed of QPSK-DPR's. A Direct Phase Regenerator (DPR) can regenerate a QPSK signal at carrier frequency. Special attention is given to jitter generation and accumulation. Circuit parameters characterizing jitter generation are clarified and obtained quantitatively. The required upper limit for jitter per DPR is also obtained from allotedC/Ndegradation in a multi-hop system. Simulation experiments were carried out using a novel 400 Mbit/s QPSK-DPR with less than 1 dB inherent equivalentC/Ndegradation. The results Show that a hybrid system, consisting of 4 to 9 DPR's and a base band regenerator, is feasible.

This paper describes a regenerator for quadriphase phase shift keying (QPSK) signals at the carrier frequency, which is called a "direct regenerator." The direct regenerator proposed here is realized using a tripler and a quadrupler. This regenerator is characterized by the symbolsm,nands, which denote the intermediate combiner amplitude ratio, the final combiner amplitude ratio and the limiter dynamic range, respectively. Complete regeneration is obtained atm = n = 1ands = \infty. Even if this condition is not satisfied, sufficient regenerative performance for practical use is preserved, when0.8 < m < 1.25, 0.7 < n < 1.4ands > 5dB. To verify the operation principle, an experiment was carried out for 1.7 GHz QPSK signals transmitted at 40 Mbits/s. It is shown that this regenerator has satisfactory decision and reshaping capability in dynamic operation. Using this direct regenerator, decision and reshaping of the QPSK signals can be made without detection. Thus, a repeater can be simplified, compared to a conventional repeater composed of a detector, a baseband regenerator and a modulator.