Abstract: A switch matrix circuit module for routing signals. In an example, the module includes a switch matrix coupled with first and second switches. The switch matrix is configured to receive a plurality of input signals, and output a selected one of the plurality of input signals as a first intermediate signal and another selected one of the plurality of input signals as a second intermediate signal. The first switch receives the first intermediate signal and a first auxiliary signal, and outputs a first output signal, and the second switch receives the second intermediate signal and a second auxiliary signal, and outputs a second output signal. A number of the modules can be coupled together to provide a switch matrix circuit, which can be readily scaled by adding further modules. In an example, the plurality of input signals are radio frequency (RF) signals.

Abstract: Techniques are provided for a multi-frequency sampling system. A system implementing the techniques according to an embodiment includes a first bandpass filter to filter a radio frequency (RF) signal to generate a first filtered signal in a first frequency band, and a second bandpass filter to filter the RF signal to generate a second filtered signal in a second frequency band. The system also includes a first analog to digital converter (ADC) operating at a first sampling frequency to convert the first filtered signal to a first digital signal and a second ADC operating at a second sampling frequency to convert the second filtered signal to a second digital signal. The first frequency band is selected to avoid a first Nyquist boundary zone associated with the first sampling frequency and the second frequency band is selected to avoid a second Nyquist boundary zone associated with the second sampling frequency.

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: A notch filter as disclosed which is adaptable to notching out a background siren from voice communications from an emergency vehicle. Two embodiments are disclosed. In the first embodiment, a frequency lock loop tracks the fundamental frequency of an electronic siren. The siren fundamental frequency is then notched out from voice transmissions using a notch filter. In the preferred transmissions using a notch filter. In the preferred embodiment, a digital ramp is generated by a first digital signal processor. This signal is input to an amplifier and a speaker thus producing an electronic siren. The digital ramp is also input to a second digital signal processor which notches out the fundamental frequency and odd harmonics thereof from the digital ramp thus acting as a comb notch filter. Analog voice is digitized by way of an analog to digital converter and input to the second digital signal processor.