Patent Number: 
Section: claims

1. A network analyzer that is connected to a test set that comprises network analyzer side ports, device under test side ports that are connected to a device under test, and a port connecter that selects any one of the device under test side ports, and connects the selected device under test side port to one of the network analyzer side ports, wherein the device under test side ports constitute a main port group and a sub port group whose connection to the network analyzer side ports is independently set, the network analyzer comprising:transmission and reception ports that are connected to the network analyzer side ports one by one, and are used to transmit and receive a signal;a transmission tracking error determiner that determines a transmission tracking error of a combination of one of the possible connections of the main port group and one of the possible connections of the sub port group for all the possible connections of the main port group based on a signal prior to transmission by said transmission and reception port, and a reception signal; anda transmission tracking error deriver that derives a transmission tracking error other than the transmission tracking errors determined by said transmission tracking error determiner based on the transmission tracking error determined by said transmission tracking error determiner. 2. The network analyzer according to claim 1,wherein said transmission tracking error deriver uses two connections other than connections at a start point and an endpoint of the transmission tracking error to be derived to derive the transmission tracking error for a combination of one of the possible connections of the main port group and another possible connection of the sub port group. 3. The network analyzer according to claim 2, wherein:the main port group includes three of the device under test side ports connected to two of the network analyzer side ports;the sub port group includes three of the device under test side ports connected to one of the network analyzer side ports; andtwo of the sub port groups exist. 4. The network analyzer according to claim 2, further comprising:a transmission signal measurer that measures a transmission signal parameter relating to a transmission signal transmitted from said transmission and reception port before a measuring system error factor is generated; anda reception signal measurer that measures a reception signal parameter relating to a reception signal received by said transmission and reception port. 5. The network analyzer according to claim 4, wherein the reception signal includes a reflected signal which is a reflected transmission signal. 6. The network analyzer according to claim 1, wherein:the main port group includes three of the device under test side ports connected to two of the network analyzer side ports;the sub port group includes three of the device under test side ports connected to one of the network analyzer side ports; andtwo of the sub port groups exist. 7. The network analyzer according to claim 1, further comprising:a transmission signal measurer that measures a transmission signal parameter relating to a transmission signal transmitted from said transmission and reception port before a measuring system error factor is generated; anda reception signal measurer that measures a reception signal parameter relating to a reception signal received by said transmission and reception port. 8. The network analyzer according to claim 7,wherein the reception signal includes a reflected signal which is a reflected transmission signal. 9. A transmission tracking error measuring method of measuring a transmission tracking error of a network analyzer that is connected to a test set that comprises network analyzer side ports, device under test side ports that are connected to a device under test, and a port connecter that selects any one of the device under test side ports, and connects the selected device under test side port to one of the network analyzer side ports, wherein the device under test side ports constitute a main port group and a sub port group whose connection to the network analyzer side ports is independently set, the network analyzer comprising transmission and reception ports that are connected to the network analyzer side ports one by one, and are used to transmit/receive a signal, the transmission tracking error measuring method comprising:realizing, in a connection operation, a combination of one of the possible connections of the main port group and one of the possible connections of the sub port group for all the possible connections of the main port group;realizing all couplings for one combination of two ports for the device under test side ports connected to the network analyzer side ports if the combination is realized by said connection operation;measuring a signal prior to being transmitted by transmission and reception port, and a resulting signal after said signal has been transmitted;determining a transmission tracking error of the coupling realized by said device under test side port coupling realizing based on a measured result of said signal measuring; andderiving a transmission tracking error other than the transmission tracking error determined by said transmission tracking error determining based on the transmission tracking error determined by said transmission tracking error determining. 10. The transmission tracking error measuring method according to claim 9,wherein said device under test side port coupling realizing is realized by a four-port calibrator which can couple all combinations of two ports out of four ports. 11. A network analyzing method of analyzing the network by using a network analyzer that is connected to a test set that comprises network analyzer side ports, device under test side ports that are connected to a device under test, and a port connecter that selects any one of the device under test side ports, and connects the selected device under test side port to one of the network analyzer side ports, wherein the device under test side ports constitute a main port group and a sub port group whose connection to the network analyzer side ports is independently set, the network analyzer comprising: transmission and reception ports that are connected to the network analyzer side ports one by one, and are used to transmit/receive a signal; the network analyzing method comprising:determining a transmission tracking error of a combination of one of the possible connections of the main port group and one of the possible connections of the sub port group for all the possible connections of the main port group based on a signal before transmitted by said transmission and reception port, and a reception signal; andderiving a transmission tracking error other than the transmission tracking errors determined by said transmission tracking error determining based on the transmission tracking error determined by said transmission tracking error determining. 12. A computer-readable medium having a program of instructions for execution by the computer to perform a processing for analyzing a network by using a network analyzer that is connected to a test set that comprises network analyzer side ports, device under test side ports that are connected to a device under test, and a port connecter that selects any one of the device under test side ports, and connects the selected device under test side port to one of the network analyzer side ports, wherein the device under test side ports constitute a main port group and a sub port group whose connection to the network analyzer side ports is independently set, the network analyzer comprising: transmission and reception ports that are connected to the network analyzer side ports one by one, and are used to transmit and receive a signal; said processing comprising:determining a transmission tracking error of a combination of one of the possible connections of the main port group and one of the possible connections of the sub port group for all the possible connections of the main port group based on a signal before transmitted by said transmission and reception port, and a reception signal; andderiving a transmission tracking error other than the transmission tracking errors determined by said transmission tracking error determining based on the transmission tracking error determined by said transmission tracking error determining.