Hee is a specification of the Winrad modes of operation, the currently implemented winrad screen frequency control, and the functions of the DLLs v1.12
Winrad Modes of Operation and Notes on Using Winrad Complex spectral displays are similar to but not quite the same as a spectrum analyzer or a panadapter display. The center of a spectrum analyzer displays the tuned frequency of the receiver or analyzer and the information is valid at all frequencies. A complex spectral display cannot provide any information about signals located at the center ferquency or close in when there is phase noise on the local oscillators. The reduced accuracy area is entirely dependent on the phase noise of all the local oscillators in the receive system. If the receiver is a single direct conversion HF receiver, and the local oscillator is low phase noise, then you may see signals or modulation as close as 10Hz from the center. If you are using a multiple IF system receiving at 10GHz or higher, then it is likely that you will mask any signals on the screen from at least -100Hz to +100Hz of the center frequency and may even extend further if the phase noise of the receiver is high. You could put the suppressed carier frequency of a SSB signal at the center and it will not hamper listening to the modulation either above or below the center. But a CW signal or steady carrier at the exact center would not be received. It is suggested that you move your signals of interest outside of the deaf center band. Therefore, as implemented in Linrad specifically with the WSE hardware, it is useful to move the local oscillator and receive frequency in large discrete steps. These steps only need to be smaller than the full displayed bandwidth so that an overlap of coverage is provided by adjacent steps. This is not a requirement and some operators prefer "tuning knob" operation by using the mouse wheel to move the entire display window. Large steps are more often used at VHF and higher, and small tuning steps are more useful at HF. This is partly due to the local oscillator implementations. Winrad Native Mode In this mode, no hardware DLLs are loaded and the only control between Winrad and any hardware is the selection of the soundcards, their modes, and their sampling rates. The center and LO frequency displayed on the Winrad screen are set manually by the operator using the mouse and its wheel, if present. The operator only needs to set the LO frequency on the screen if he wants to read the true signal frequency that is read by the mouse cursor position. If the LO frequency is left at zero, then the cursor readout will be a positive or a negative number at baseband. Winrad Mode 2 In this mode, a DLL unique to the specific receiver or transceiver is loaded. This hardware has a complex baseband output and if capable of transmit, also has a complex baseband input. Whether the hardware is a synthesized softrock or is a multiple IF superheterodyne such as the WSE hardware, the LO or receive frequency is communicated to Winrad via the loaded DLL. It is then displayed on the Winrad screen. This frequency may be one fixed frequency or may be adjustable in any step size. It is recommended but not required that the steps be in 50KHz increments for 96KHz soundcards or 100KHz for 192KHz soundcards. The operator may change the LO frequency using the mouse by adjusting the numeric display on the Winrad screen. This change to the LO frequency will be communicated to your hardware via the loaded DLL. By also pressing the CTRL key when you are changing the frequency digits (Winrad ver 1.25 and later) you will simultaneously change the internal software oscillator of Winrad so the reception frequency will remain in the same. If the only control of the hardware is its frequency, then no gui is required and the DLL is simple. If the hardware also controls other functions such as antenna selector, RF pre-selectors, attenuators, and pre-amplifiers, then a DLL with a gui window must be written since those are not on the Winrad screen. If the hardware is capable of transmit, then a means of controlling and communicating a separate transmit frequency must be provided. Winrad Mode 3 Some hardware such as the SDR-14, SDR-IQ, the HPSDR and Phil Covington projects have wideband general coverage, a built-in digital downconverter, and built-in digital to analog converters, usually with non-standard sampling rates. Thus no high sampling rate input soundcard is needed. The custom DLL for that hardware needs to have a gui and a separate screen because it must control the frequency, the sampling rate, and antenna selector, RF pre-selectors, attenuators, and pre-amplifiers. A very modest soundcard is needed for the audio output. This can be the one built on your computer's motherboard. Winrad and Transmit Control When appropriate hardware is available, an extended version of Winrad will be developed. In addition to DLL control of the hardware functions, the frequency of the transmitter must be be displayed since most operating is split frequency. The T/R timing will also control which Winrad processes are running. 73, Jeffrey Pawlan, WA6KBL and Alberto, I2PHD _______________________________________________ Winrad mailing list [email protected] http://winrad.org/mailman/listinfo/winrad_winrad.org
