Portsdown Signal Generator - Revision history

G8GKQ: /* Starting the Signal Generator */

2019-07-05T16:28:03Z

Starting the Signal Generator

G8GKQ at 15:41, 8 September 2018

2018-09-08T15:41:15Z

G8GKQ: /* Starting the Signal Generator */

2018-08-10T16:07:52Z

Starting the Signal Generator

G8GKQ: /* Frequency Control */

2018-01-12T21:26:39Z

Frequency Control

G8GKQ: /* Express */

2018-01-12T21:25:26Z

Express

G8GKQ: /* Frequency Control */

2018-01-12T21:24:35Z

Frequency Control

G8GKQ: /* Level Control */

2018-01-12T21:23:34Z

Level Control

G8GKQ at 15:38, 12 January 2018

2018-01-12T15:38:42Z

G8GKQ at 15:38, 12 January 2018

2018-01-12T15:38:27Z

G8GKQ: /* Modulation = */

2018-01-12T15:37:12Z

Modulation =

@@ Line 3: / Line 3: @@
 === Starting the Signal Generator ===
-The Portsdown Signal Generator is accessed from Menu 3 of the Portsdown Transmitter touchscreen.  When the "Sig Gen" is started it stops the Portsdown Transmitter application, and starts the signal generator.  On exit from the signal generator the Portsdown Transmitter is restarted (in a standby state) on Menu 1.  The Signal Generator is only controlled from the touchscreen and cannot be controlled from the console.
+The Portsdown Signal Generator is accessed from Menu 2 of the Portsdown Transmitter touchscreen.  When the "Sig Gen" is started it stops the Portsdown Transmitter application, and starts the signal generator.  On exit from the signal generator the Portsdown Transmitter is restarted (in a standby state) on Menu 1.  The Signal Generator is only controlled from the touchscreen and cannot be controlled from the console.
 The signal generator starts with the last saved configuration (as saved from the Frequency Screen) and with the output and modulation off.  The Configuration Screen is shown at startup.

@@ Line 25: / Line 25: @@
 ==== Attenuator ====
-The attenuator button is used to allow for the use of an external software-controlled attenuator of the PE43703, PE43713, PE4302, PE4312 or HMC1119 type available from eBay.  Full details can be found on this page [[Output Attenuator]].  The specific type of attenuator is set from the setup menu of the console.  The support for these attenuators is currently only implemented for the Signal Generator, not the DATV Transmitter.  Whilst in use, the setting of the attenuator is displayed on the Frequency page.
+The attenuator button is used to allow for the use of an external software-controlled attenuator of the PE43703, PE43713, PE4302, PE4312 or HMC1119 type available from eBay.  If the button is Blue, no Attenuator is assumed to be used.  If the button is green, the software assumes that an attenuator is in-circuit.  The attenuation provided is controlled (set) by the demanded output level on the "Freq" screen.  Full details can be found on this page [[Output Attenuator]].  The specific type of attenuator is set from the setup menu of the console.  Whilst in use, the setting of the attenuator is displayed on the Frequency page.
 ==== Modulation ====

← Older revision		Revision as of 16:07, 10 August 2018
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	The Portsdown can be set to boot directly into the Signal Generator and turn the output on (using the saved settings). This capability can be enabled from the Setup, Autostart menu on the console.		The Portsdown can be set to boot directly into the Signal Generator and turn the output on (using the saved settings). This capability can be enabled from the Setup, Autostart menu on the console.
−
−	There is an unresolved issue with the software appearing to freeze with the BATC Logo on the screen after switching back and forth between the Signal Generator and the DATV transmitter more than 3 times. Normal service can be restored by rebooting the RPi.

	=== Controlling the Signal Generator ===		=== Controlling the Signal Generator ===

← Older revision		Revision as of 21:26, 12 January 2018
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	The small size of the buttons has highlighted some issues in registration between touchscreens and displays. Run the calibration utility on Menu 3 and you will be surprised at how much more responsive it makes the screen feel.		The small size of the buttons has highlighted some issues in registration between touchscreens and displays. Run the calibration utility on Menu 3 and you will be surprised at how much more responsive it makes the screen feel.
		+
		+	The frequency displayed on the touchscreen is the "demanded frequency". Due to limitations in the Analog Devices software driver being used, the generated frequency in Portsdown and ADF4351 modes will step at intervals of about 1/500,000th of the selected frequency. For example, the step at 1240 MHz is about 3KHz.

	===== Level Control =====		===== Level Control =====

@@ Line 79: / Line 79: @@
 Software Version 201801061 introduced the capability to use the DATV Express board as a very capable signal generator covering 70 - 2450 MHz at levels from -30dBm to +17dBm.
-Additionally, the DATV Express can be used a DVB-S test source for checking amplifier linearity.  Selecting the "Mod" button applies 333KS QPSK DVB-S modulation with an H264-coded image.  If the amplifier output is viewed on a spectrum analyser (or an RTL-SDR with a program such as SDR# on a PC or FreqShow on another Raspberry Pi), the level can then be adjusted appropriately to prevent too much spectral regrowth.
+Additionally, the DATV Express can be used as a DVB-S test source for checking amplifier linearity.  Selecting the "Mod" button applies 333KS QPSK DVB-S modulation with an H264-coded image.  If the amplifier output is viewed on a spectrum analyser (or an RTL-SDR with a program such as SDR# on a PC or FreqShow on another Raspberry Pi), the level can then be adjusted appropriately to prevent too much spectral regrowth.
 The estimated DATV Express RF output level is displayed, together with the DATV Express attenuator level setting (on the frequency page).

@@ Line 93: / Line 93: @@
 The second row shows the current selected frequency on Hz.  Depending on the available frequency range of the selected output, blue buttons above and below each digit enable the frequency to be adjusted.  This adjustment is limited to the valid frequency range for the selected output and any buttons that are not required are hidden.
-The small size of the buttons has highlighted some issues in registration between touchscreens and displays.  It is hoped to provide a calibration utility for the and the Portsdown DATV transmitter soon.
+The small size of the buttons has highlighted some issues in registration between touchscreens and displays.  Run the calibration utility on Menu 3 and you will be surprised at how much more responsive it makes the screen feel.
 ===== Level Control =====

← Older revision		Revision as of 21:23, 12 January 2018
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	The Save button saves the current settings for use as the default configuration. It is this saved setting that will be used when the Signal Generator is next started, not the last setting used before shutdown.		The Save button saves the current settings for use as the default configuration. It is this saved setting that will be used when the Signal Generator is next started, not the last setting used before shutdown.

−	The Mod button ~~is planned to have~~ the same functionality as the Mod button on the Configuration Screen ~~but is not yet functional~~.	+	The Mod button has the same functionality as the Mod button on the Configuration Screen.

← Older revision		Revision as of 15:38, 12 January 2018
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−	Software release ~~201801060~~ develops the capability to use the Portsdown as a capable signal generator covering 35 MHz to 4.2 GHz.	+	Software release 201801061 develops the capability to use the Portsdown as a capable signal generator covering 35 MHz to 4.2 GHz.

	=== Starting the Signal Generator ===		=== Starting the Signal Generator ===

@@ Line 29: / Line 29: @@
 The attenuator button is used to allow for the use of an external software-controlled attenuator of the PE43703, PE43713, PE4302, PE4312 or HMC1119 type available from eBay.  Full details can be found on this page [[Output Attenuator]].  The specific type of attenuator is set from the setup menu of the console.  The support for these attenuators is currently only implemented for the Signal Generator, not the DATV Transmitter.  Whilst in use, the setting of the attenuator is displayed on the Frequency page.
-=== Modulation ====
+==== Modulation ====
-Selecting the "Mod" button applies 333KS QPSK DVB-S modulation with an H264-coded image to the Portsdown output or the DATV Express output.  It is inoperative in other miodes.
+Selecting the "Mod" button applies 333KS QPSK DVB-S modulation with an H264-coded image to the Portsdown output or the DATV Express output.  It is inoperative in other modes.  The estimated power level is adjusted to take account of the effects of the modulation.
 ==== Presets ====