Abstract: In the present technique for transmitting and delaying radio frequency signal transmission, an RF delay filter (102) is provided with at least one high permittivity material coaxial delay element (104) with each having an input port (114) and an output port (116). Multiple coaxial delay elements are operably coupled by a quarter-wave microstrip transmission line (230) to offset any frequency mismatch at the band edges of the delay elements. A series of capacitors (126, 128) are also included at each port of the coaxial elements to compensate for any resultant parasitic inductance.

Abstract: Briefly, according to the invention, a multi-unit communication device having a transceiver unit 108 and a control unit 104 is provided. The transceiver unit 108 transmits and receives information signals having digital and analog portions. The control unit 104 provides for operator interface to the communication device. The communication between the transceiver unit 108 and the control unit 104 is conducted on a single pair of wires 112 using ISDN format.

Abstract: An essentially zero intermediate frequency receiver (100) for recovering an information signal from a received signal (110), which includes means for blanking noise signals which may otherwise deteriorate performance, comprises a receiver (10) for recovering the information signal and a noise blanker (28). The receiver (28) comprises at least one conversion mixer (32B) for operating on the received signal (110) to provide an essentially baseband signal (125B), at least one delay filter (40B) coupled to the conversion mixer (32B) for producing a delayed essentially baseband signal, and at least one blanker switch (S1-S4) for operating on the delayed essentially baseband signal to temporarily prevent recovery of the information signal in response to a control signal (58). To provide the control signal (58), the noise blanker (28) is coupled to the receiver (10) for operating on either the essentially baseband signal (125B) or the received signal (110) as a noise blanker input signal.

Abstract: A radio receiver capable of receiving more than one channel, one of which channels may be a priority channel, wherein some communications may be accompanied by a sub-audible continuous identifying signal, which signal can be detected by the radio in an adaptive way. In particular, a wideband, rapid detect approach can be utilized in the absence of a determination that adjacent identifying signals are present. To the extent such adjacent signals are present, the radio selects a narrowband, slower detection approach, or, in the alternative, shifts the bandpass characteristics of the wideband approach in an attempt to avoid the adjacent interfering signal.

Abstract: A mobile radio receiver employs an SAW filter to provide an appropriate time delay to enable an extender to effectively blank the recovered signal thereby preventing noise from entering the IF section of the radio. The SAW filter allows long signal delays without significant pulse stretching while also allowing narrow IF bandwidths. The control pulse to the blanker switch is shaped to reduce the coupling of noise generated within the blanker switch from the received signal path. The operation of the extender is controlled by the main receiver through an AGC signal to determine when, and to what extent, the extender is enabled.